Optical reader comprising multiple color illumination

ABSTRACT

An imaging module in one embodiment includes at least one multiple color emitting light source comprising a plurality of different colored LED dies each independently driveable so that the overall color emitted by the light source can be controlled and varied. The multiple color emitting light source can be controlled so that the color emitted by the light source is optimized for imaging or reading in a present application environment of the module. Further, the module can be configured so that control of the multiple color emitting light source automatically varies depending on a sensed condition, such a color present in a field of view of the module, the distance of the module to a target, and/or a predetermined criteria being met so that feedback is provided to a user. The module in a further aspect can include illumination light sources and aiming light sources which project light in different wavelength emission bands.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of application Ser.No. 09/802,579, filed Mar. 8, 2001, entitled “Imaging Module for OpticalReader Comprising Refractive Diffuser,” which is a continuation-in-partof application Ser. No. 09/411,936, filed Oct. 4, 1999, entitled“Imaging Module for Optical Reader.” The priorities of both the Ser.Nos. 09/802,579 and 09/411,936 applications are claimed and both of theabove applications are incorporated in their entireties by reference.This application also claims priority of the following five provisionalapplications: U.S. Serial No. 60/301,036, filed Jun. 26, 2001, entitled“Data Collection Miniature Imaging Module and Aimer Device,” U.S. SerialNo. 60/327,249, filed Oct. 5, 2001, entitled “Multicolor Optical ReaderIllumination,” U.S. Serial No. 60/322,776, filed Sep. 11, 2001, entitled“Data Collection Miniature Imaging Module and Aimer Device, U.S. SerialNo. 60/328,855, filed Oct. 12, 2001, entitled “Optical Reader ComprisingConductive Support Posts,” and U.S. Serial No. 60/345,523, filed Nov. 9,2001, entitled “Optical Reader Module Comprising Alignment Elements.”The content of each of the above five provisional applications is reliedupon and incorporated herein by reference. The benefit of each of theabove five provisional application's respective priority is herebyexpressly claimed in accordance with 35 U.S.C. §119(e).

FIELD OF THE INVENTION

[0002] The invention relates to optical readers in general andspecifically to an optical reader imaging module which emits light inmore than one visible color wavelength band.

BACKGROUND OF THE PRIOR ART

[0003] Most image signal generating data collection devices.

BACKGROUND OF THE PRIOR ART

[0004] Most image signal generating data collection devices requirebuilt-in illumination elements for illuminating a target area. The builtin illumination elements and structural members supporting them consumesubstantial space. Laser scanner based imaging modules are becomingavailable in increasingly small sizes. The Symbol SE900 imaging moduleis an example of a small-sized laser based image imaging module. Theface profile of the SE900 module is about 0.81″ wide (“x”)×0.45″ high(“y”).

[0005] Certain problems have been noted with laser based imagingmodules, however. First, laser based imaging modules are not welladapted to capture 2D images and therefore cannot be utilized in asystem for decoding certain types of 2D indicia such as 2D matrix barcodes and OCR characters. Although existing laser based imaging modulesread stacked 2D symbologies such as PDF417, they typically are notappropriate for the capture of 2D images. Attempts to adapt a laserscanner based image engine for 2D image capture have been unsuccessful.Laser scanning 2D image engines, while generating low resolution imagesignals, have been observed to be costly, and space consuming. Anothermajor problem noted with laser based bar codes is their lack ofdurability. Laser scan engine modules require a moving mirror which isdelicately mounted. Mirror mount structure can easily be misaligned orbroken by sudden impact of a housing incorporating the module on a rigidobject. The mechanical complexity of a laser scanner based imagingmodule increases significantly if the module must generate 2D imagesignals.

[0006] In spite of the significant problems relating to laser scannerimaging modules in their inability to read 2D indicia, and theirfragility, some users of dataform reading instruments continue to beimpressed with certain advantages that are exhibited by them. First, asmentioned, laser scanner based imaging modules, because of their limitedfunctionality can easily be made in packages of reduced size and weight.Second, some users react positively to the neat and clean aiming andillumination pattern that is projected onto a target by a laser scannerbased imaging module. Laser scanner based imaging modules project acollimated narrow beam of light onto a target. The beam is scanned todefine an aiming line. Because the line is well defined, users canreadily locate the scan line on an indicia to be read within a targetarea. The positioning of an imaging module aiming pattern is sometimesreferred to as “sighting” a target indicia.

[0007] It would be desirable to incorporate the size packaging andsighting advantages presently exhibited by laser scanner imaging modulesinto a highly durable image sensor based imaging module which exhibitsthe traditional performance and durability advantages of image sensorbased imaging modules.

SUMMARY OF THE INVENTION

[0008] In accordance with its major aspects and broadly stated, theinvention is an imaging module including a printed circuit board, animage sensor electrically connected to the printed circuit board, asupport assembly for supporting at least one optical element, and anillumination system for generating an illumination pattern onto atarget. The illumination system may include illumination light sourcesand diffusers for diffusing light from the illumination light sources.The module may further include an aiming system having an aiming lightsource, an aperture for stopping light from the aiming light source, andan optical element for projecting an aiming pattern into target area.For the reduction of the size of the module either or both of theillumination and aiming systems may include light redirecting elementssuch as mirrors or prisms.

[0009] In another aspect, the imaging module may include support postsfor supporting various components of the imaging module. The module mayinclude a first circuit board carrying an image sensor, a second circuitboard carrying at least one light source, a support assembly interposedbetween the first and second circuit boards, and aligned post holes oneach of the first circuit board, second circuit board, and supportassembly for accommodating several support posts which, whenaccommodated in the post holes, support the structure including thesupport assembly interposed between two circuit boards. The supportposts may be made electrically conductive so as to avoid a need toprovide an additional electrical connector between the first and secondcircuit boards.

[0010] In another aspect, the imaging module may incorporate an aimingsystem including a light source, an aperture and an optical elementpositioned optically forward of the aperture wherein the aiming systemprojects a crisp and sharp aiming pattern onto a target over a widerange of distances. In one embodiment, an aiming system is configured sothat a lens aperture effect results in a crisp sharp aiming pattern overa wide range of distances including distances at which the aimingpattern is less than optimally focused. In another embodiment an aimingsystem is configured so that light emanating from a thin aperture isimaged in such a manner that a crisp, sharp aiming pattern is definedover a wide range of distances. The aiming pattern in one embodimentincludes sharply defined lateral edges which are useful in sightingtarget indicia.

[0011] In still another aspect, the module of the invention can includeat least one multiple color emitting light source comprising a pluralityof different colored LED dies each independently drivable so that theoverall color emitted by the light source can be controlled and varied.The multiple color emitting light source can be controlled so that thecolor emitted by the light source is optimized for imaging or reading ina present application environment of the module. Further, the module canbe configured so that control of the multiple color emitting lightsource automatically varies depending on a sensed condition, such acolor present in a field of view of the module, the distance of themodule to a target, and/or a predetermined criteria being met so thatfeedback is provided to a user. The module in a further aspect caninclude illumination light sources and aiming light sources whichproject light in different wavelength emission bands.

[0012] With the substantial size reductions made possible witharchitectures according to the invention, the positioning between a lensassembly and an image sensor can significantly affect the performance ofthe module. Accordingly, an imaging module in accordance with theinvention may be adapted so that a position of a lens assembly can befinely adjusted relative to a position of an image sensor. A retainerand lens assembly according to the invention are complimentarilyconfigured so that the lens assembly is slidably received in theretainer. The retainer includes two apertures defined in sidewallsthereof. The first aperture accommodates a fixture pin for use in finelyadjusting the position of the lens assembly within the retainer. Thesecond aperture accommodates an adhesive material for adhesively bondingthe lens assembly to the retainer. Adhesive material may further beapplied in the first aperture.

[0013] In a still further aspect of the invention, a module according tothe invention can include aiming and illumination light sources havingimproved architectures. Light sources incorporated in the module caninclude surface integrated LEDs in which part of the light source isdefined by a printed circuit board. Use of surface integrated LEDs in amodule appropriately configures substantially reduces a dimension of themodule in at least one plane. The module can also incorporate sideleaded surface mount LEDs which can be firmly benched against a printedcircuit board to achieve precision alignment of the LEDs withoutadditional aligning members or alignment aiding assembly steps.

[0014] In yet another aspect of the invention, a module according to theinvention can include one or more heat sink structures for reducing atemperature of the module. In another aspect, support posts of themodule are utilized for purposes other than structurally supporting andelectrically connecting members of the module. The support posts can beutilized to attach additional structural members (e.g. PCBs, opticalplates, heat sink structures) which can be considered part of the modulewhen they are attached. The support posts can also be utilized inmounting, supporting, or stabilizing the module in a housing interiormember or on another member on which the module may be attached. Themodule may further include an “unpackaged” image sensor which ismanufactured to be devoid of at least one of its traditional componentsso that a further size reduction of the module is realized. In a stillfurther aspect of the module, the module may include a flexible circuitboard so that the shape of the module can be varied, rendering themodule fittable into a variety of cavity configurations. The module canalso include light pipes for directing light from a light source into atarget area.

[0015] With the significant miniaturization achievable with modulearchitectures according to the invention, the module can readily befittable into instrument or device housings of small size which becomeoptical readers with the module installed therein. Modules according tothe invention can be installed for example in gun style reader housings,personal data assistants (PDAs), portable data terminals (PDTs), mobiletelephones, calculators, wrist watches, finger worn “ring scanners,”writing implements such as pens, and numerous other devices.

[0016] These and other aspects of the invention will be described infurther detail herein with reference to the below listed drawings, anddetailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIGS. 1a-1 b show front and rear perspective views of an imagingmodule according to the invention;

[0018]FIGS. 1c-1 g are top, bottom, front, back, and side views of animaging module according to the invention;

[0019]FIG. 1h is a perspective assembly view of the imaging module shownin FIG. 1a;

[0020]FIGS. 1i-1L are perspective views of various component parts ofthe imaging module shown in FIG. 1a;

[0021]FIG. 1n is a cross sectional view of the optical plate shown inFIG. 1m looking in the direction indicated by lines b of FIG. 1m;

[0022]FIG. 1o is a perspective assembly view of an alternativelydesigned imaging module of the invention;

[0023]FIGS. 1p and 1 q are partial assembly views showing alternativelydesigned component parts of an imaging module of the invention;

[0024]FIG. 1r is an exploded view of a support post according to theinvention;

[0025]FIG. 1s is a perspective view of an embodiment of a supportassembly of the invention;

[0026]FIG. 1t is a perspective view of an aperture plate in accordancewith one embodiment of the invention;

[0027]FIG. 1u is a perspective view of an assembled imaging module asshown in the assembly state view of FIG. 1o;

[0028]FIG. 1v is a perspective view of a support assembly according tothe invention including elongated struts;

[0029]FIG. 2a is a perspective view of an imaging module according tothe invention including surface integrated LEDs;

[0030]FIGS. 2b-2 d are top, front, and side views of the module shown inFIG. 2a;

[0031]FIGS. 2e, 2 f, 2 g, and 2 h show perspective views of alternativeimaging modules according to the invention;

[0032]FIGS. 2i, 2 j, and 2 k show perspective views of imaging modulesillustrating functionality of support posts of the imaging module;

[0033]FIG. 2L is an assembly perspective view of another imaging moduleaccording to the invention;

[0034]FIGS. 2m and 2 l are assembly state views of an imaging module ofthe invention including a support assembly having a frame;

[0035]FIGS. 2n and 2 p are front and rear perspective views of theassembled module shown in FIGS. 2m and 2 o;

[0036]FIG. 3a is a perspective view of an alternative imaging module ofthe invention;

[0037]FIG. 3b is a cutaway perspective view of the module shown in FIG.3a;

[0038]FIG. 3c is a side view of the module of FIG. 3a;

[0039]FIG. 3d is a rear perspective view of the module of FIG. 3a;

[0040]FIG. 3e is a perspective view of an alternative imaging module ofthe invention including a single horizontal row of LEDs and a supportframe supported entirely by a printed circuit board;

[0041]FIG. 3f is a cutaway perspective view of the module of FIG. 3e;

[0042]FIG. 3g is a cutaway side view of the module of FIG. 3e;

[0043]FIG. 3h is a top view of the module of FIG. 3e;

[0044]FIGS. 3i, 3 j, 3 k, and 3L are perspective views of alternativeimaging modules according to the invention;

[0045]FIGS. 4a, 4 b, and 4 d are perspective views of an imaging moduleaccording to the invention including a flexible circuit board and lightpipes for directing light toward a target area;

[0046]FIG. 4c is a side view of the module shown in FIG. a;

[0047]FIGS. 4e and 4 f are partial side views of an imaging moduleincluding bendable light pipe illumination;

[0048]FIGS. 4g, 4 h, and 4 i are perspective, front, and side cutawayviews of an imaging module according to the invention including moldedlight pipes;

[0049]FIG. 4j is a perspective view of the module of FIG. 4g havingdashed in lines indicate structure hidden from view.

[0050]FIGS. 4k, 41, 4 m, and 4 n are front perspective, rearperspective, front, and cutaway side views of a module according to theinvention including folded receive optics and light pipe targetillumination;

[0051]FIG. 5a is a diagram illustrating an appearance and a method forgenerating illumination pattern according to the invention;

[0052]FIGS. 5b and 5 c illustrate molds which may be utilized in themanufacture of an optical plate according to the invention;

[0053]FIG. 5d is an exploded perspective view of an optical plate of theinvention including cylindrical microlenses;

[0054]FIG. 5e is an exploded partial view depicting a surface of theoptical plate shown in FIG. 5d;

[0055]FIG. 5f is a cross sectional exploded top view of the opticalplate of FIG. 5d;

[0056]FIGS. 5g-5 k illustrate top cutaway views of various opticalplates according to the invention taken along a row of illuminationlight sources;

[0057]FIG. 5L is a partial cutaway side view of an imaging module of theinvention including a solitary horizontal row of light sources;

[0058]FIGS. 6a-6 g illustrate various views, including perspective,side, and partial assembly views of an imaging module according to theinvention having aiming light sources mounted to a circuit board whichcarries an image sensor;

[0059]FIGS. 6h, 6 i, and 6 j are diagrams illustrating various aimingand illumination patterns which may be projected onto a target by amodule of the invention;

[0060]FIG. 6k is a perspective view of an imaging module according tothe invention which incorporates aiming light sources provided by laserdiodes;

[0061]FIG. 6L is a diagram of an illumination pattern and an aimingpattern which may be projected by the module of FIG. 6k;

[0062]FIG. 6m is a perspective view of an imaging module of theinvention, which is well suited for carrying a 1D image sensor;

[0063]FIGS. 6n, 6 o, and 6 p are side view functional diagramsillustrating various folded optic aiming systems which may beincorporated in the invention;

[0064]FIG. 6q is a cutaway side view of a module according to theinvention having a molded light pipe incorporating an aperture aimingsystem;

[0065]FIG. 6r is a rear perspective view of an optical plate accordingto the invention adapted for generating a split line aiming pattern;

[0066]FIG. 6s is a top cutaway view of the optical plate of FIG. 6rlooking in the direction of arrows A of FIG. 6r;

[0067]FIG. 6t is a rear perspective view of another optical plateaccording to the invention adapted for generating a split line aimingpattern;

[0068]FIG. 6u is a top cutaway view of the optical plate of FIG. 6tlooking in the direction of arrows A of FIG. 6t;

[0069]FIGS. 6v, 6 w, and 6 x are top cutaway top views of variousoptical plates according to the invention taken along a line of aiminglight sources;

[0070]FIG. 6y is a side view light ray diagram illustrating apertureeffect of an aiming optical element according to the invention in oneembodiment;

[0071]FIG. 6z is a side view light ray diagram corresponding to anaiming system of the invention having a thin aperture;

[0072]FIGS. 7a-7 d illustrate an aiming pattern projected by the aimingsystem described in connection with FIG. 6z at various module to targetdistances.

[0073]FIG. 7e illustrates a side view of a side-leaded surface-mountedLED which may be incorporated in a module according to the invention;

[0074]FIG. 8a is a side view of a circuit board according to theinvention having surface integrated LEDs integrated therein;

[0075]FIG. 8b a top view of a circuit board according to the inventionhaving surface integrated LEDs integrated therein;

[0076]FIGS. 8c, 8 d, and 8 e show side schematic use of various lightpipe aiming and illumination configurations which may be incorporated ina module of the invention;

[0077]FIGS. 8f and 8 g are schematic views of modified light sourceswhich can be incorporated in an imaging module of the invention;

[0078]FIG. 8h is a perspective view of an imaging module of theinvention incorporating a multiple color emitting light source;

[0079]FIG. 8i is an exploded perspective view of a multiple coloremitting light source according to the invention;

[0080]FIG. 8j is a diagram illustrating exemplary aiming andillumination pattern which may be projected by a module of the inventionhaving an aiming light source and an illumination light source atdifferent wavelength bands;

[0081]FIG. 8k is an optical reader, which is programmed to generate auser interactive menu screen allowing a user to change a color emissionoutput certain of the light sources of the module;

[0082]FIG. 8L is a perspective view of a support assembly including alens assembly retainer adapted to receive a threadless lens barreltherein;

[0083]FIG. 8m is a top perspective view of a lens assembly lens barrelshowing a pin receiving notch thereon;

[0084]FIG. 8n is a bottom perspective view of the barrel shown in FIG.8m showing a glue receiving surface of the barrel;

[0085]FIG. 8o is a cutaway top view of an imaging module of theinvention showing a lens retainer and barrel detail thereof;

[0086]FIGS. 8p and 8 q show views of a fixture which may be utilized inprecision mounting of a lens assembly within a lens retainer accordingto the invention;

[0087]FIG. 8r is a side view of a lens retainer and lens systemaccording to the invention including threads;

[0088]FIGS. 8s and 8 t are side views of an unpackaged image sensoraccording to the invention, as mounted on a printed circuit board;

[0089]FIG. 8u is a side view of a printed circuit board having an imagesensor window in accordance with the invention;

[0090]FIG. 8z is a perspective view of a traditional prior art imagesensor chip;

[0091]FIG. 8y shows a perspective view of an alternative barrel having aconcave glue receiving surface.

[0092]FIGS. 9a-9L show perspective views of various devices having animaging module according to the invention incorporated therein;

[0093]FIG. 9m shows a side view mounting detail diagram for illustratinghow a post-containing imaging module of the invention may be mounted;

[0094]FIGS. 10a-10 e are electrical circuit diagrams associated with theinvention, depicting electrical circuitry which can at least partiallybe incorporated on a printed circuit board of an imaging moduleaccording to the invention;

[0095]FIG. 11 is an internal side view of a prior art imaging module.

DETAILED DESCRIPTION OF THE INVENTION

[0096] Description of the invention is broken down into the followingeight subheadings: (A) General Imaging Module Architectures andAssembly, (B) Illumination Systems; (C) Aiming Systems, (D) IlluminationDevice Architectures; (E) Illumination/Aiming Color Emission Control andCoordination; (F) Receive Optics, (G) Packaging of Electronics; and (H)Applications, Operating Environment, and Control Circuit Functionality.It will be understood that the above subheadings are intended to providea general separation the various topics discussed in the specificationonly, and that description of certain features of the invention is inseveral instances included under more than one subheading.

[0097] A. General Module Architectures and Assembly Method

[0098] A first embodiment of an imaging module according to theinvention are shown in FIGS. 1a-1 g. Imaging module 10, 10-1 includes afirst circuit board 14 a carrying an image sensor 32 typically providedby an image sensor chip and aiming light sources 18, and a secondcircuit board 14 b carrying illumination light sources 16. The first andsecond circuit boards 14 a and 14 b are supported by a support assembly80. Support assembly 80 in module 10-1 includes a containment section 81for containing image sensor 32 and an integrated retainer section 82 forretaining a lens assembly 40. Support assembly 80 of module 10-1 alongwith first circuit board 14 a and second circuit board 14 b furtherinclude post holes 83 for receiving support posts 84. Module 10-1includes four support posts 84, each of which extends through firstcircuit board 14 a, support assembly 80, and second circuit board 14 b,and thereby aids in holding of the various components of moduletogether. Imaging module 10-1 further includes optical plate 26 whichcarries various emit optical elements. Optical plate 26 of module 10-1includes illumination optics 27, 28 (see FIG. 1n) for aiding in thedevelopment of a substantially uniform illumination pattern over atarget area corresponding to a field of view of image sensor 32, andaiming optics 25 for aiding in the projection of an aiming pattern in atarget area. Both second circuit board 14 b and optical plate includecentral apertures 836, 837 for accommodating retainer section 82 whenthey are moved toward support assembly 80. With the architecturesdescribed, substantial miniaturization of the imaging module achieved.Module 10-1 may have a width dimension of about 0.810 in., a heightdimension of about 0.450 in., and a depth dimension of about 0.560 in.Aiming and illumination light sources 16, 18 of module 10-1 are providedby surface mounted and back benched LEDs having side-extending leads or“gull wings.”

[0099] Further aspects of imaging module 10-1 are described withreference to FIGS. 1h through 1 n. In FIG. 1h an assembly diagramillustrating components of module 10-1 in an unassembled state aredescribed. In FIG. 1h it is seen that first circuit board 14 a carriesimage sensor 32 provided by a image sensor chip, and a pair of aiminglight sources 18 provided by LEDs. Support assembly 80 of module 10-1includes containment section 81, which as best seen by the internal viewof FIG. 1k, provides containment for image sensor 32, preventing damagethereto, and preventing stray light rays from reaching image sensor 32.Support assembly 80 further includes an integrated retainer section 82for retaining a lens assembly 40 as will be described in further detailherein. Referring to further aspects of support assembly 80, supportassembly 80 of module 10-1 includes integrated struts 80 st, havingformed therein post holes 83 as have been discussed herein, andapertures 43, for aiding in the formation of an aiming pattern as willbe described in further detail herein. Still further, shown by FIG. ii,support assembly 80 can include integrated mounting wings 80 w, foraiding in the mounting of imaging module 10-1 on a member external tomodule 10-1, such as a member located on an interior of a portableoptical reader housing, a PDA, a PDT, or a cellular phone, etc. Secondcircuit board 14 b and optical plate 26 each includes a central aperture836 and 837 for accommodating retainer 82. Mounting wings 80 w includescrew holes 810 for receiving mounting screws. Screw holes 810 may alsobe included in support assembly main body as are labeled in FIG. 1h.Support assembly 80 in the embodiment of FIG. 1i is a one piece unitcomprising a containment section 81 a retainer section 82, struts 80 st,aiming apertures 43, and mounting wings 80 w.

[0100] Referring to FIGS. 1h, 1 j, 1 k, and 1L together it is seen thateach of printed circuit board 14 a, support assembly 80, printed circuitboard 14 b, and optical plate 26 includes a plurality of key structureswhich interlock a complementary key structure of its neighboringcomponent part or parts. In particular, first circuit board 14 aincludes a pair of key apertures 812 which receive key pins 81 h ofsupport assembly 80. Forward end 816 of support assembly 80 alsoincludes key pins 820 which are matingly received by key apertures 822of second circuit board 14 b. Second circuit board 14 b further includeslateral key apertures 826 for receiving key side pins 830 of opticalplate 26, and center key holes 834 for receiving key center pins 840 ofoptical plate 26. Key center pins 840 as best seen in FIGS. 1j and 1 ipenetrate straight though key holes 834 of printed circuit board 146 andare received by key holes 842 of support assembly 80. The various keystructures described herein above aid in properly aligning the variouscomponent parts of module 10-1 and greatly reduce the amount of shiftingbetween component parts of module 10-1 in the XY plane after thecomponent parts are assembled. Module 10-1 further includes elementswhich aid achieving proper Z-direction spacing between component partsof module 10-1. As seen in FIG. 1h support assembly 80 includes a pairof top and bottom integrated spacer ridges 846 for aiding in properlyspacing support assembly 80 with second printed circuit board 14 b.Aperture defining member 848 of support 80 is also raised and flattenedto aid achieving proper spacing between assembly 80 and board 14 b.Optical plate 26 also includes various spacing aiding members.Specifically, optical plate 26 includes a spacer ring 852 and a spacerridge 854. Spacer ring 852 and spacer ridge 854 are sized and configuredso that when optical plate 26 is pushed toward printed circuit board 14b, proper spacing between plate 26 and board 14 b is achieved. Proper Zdirection spacing between components of module can also be aided withuse of support post ring spacers and or steps to be described herein.Referring to further aspects of module 10-1, plate 28 includes cavities857 which receive LEDs 16. By receiving LEDs 16, cavities 857 provide afurther reduction in the depth dimension of module 10-1. While imagingmodule described herein are in most cases shown as supporting a 2D imagesensor, it will be appreciated that the architectures of the imagingmodules herein described are also useful for supporting 1D imagesensors.

[0101] One variation of imaging module 10-1 according to the inventionis shown in FIG. 2a. Like module 10-1, module 10-2 in the embodiment ofFIGS. 2a-2 c includes a support assembly 80, a first circuit board 14 a,a second circuit board 14 b, and support posts 84 for structurallysupporting the above components. However, module 10-2 does not include alens plate 26 as in module 10-1. Further, unlike module 10-1, module10-2 includes surface integrated LEDs wherein dies of LEDs are depositeddirectly onto a printed circuit board. Aiming LEDs 18 and illuminationLEDs 16 of module 10-2 shown in FIGS. 2a-2 d are provided by surfaceintegrated LEDs. Support assembly 80 in the embodiment of FIG. 2aincludes a barrel shaped retainer section 82 and a containment section81. Retainer section 82 retains a lens assembly 40 which may include asingle element or a multiple element imaging lens incorporated in a lensbarrel. Containment section 81 contains an image sensor 32 as will bedescribed in further detail herein. Support assembly 80 further includesstruts 80 st on which printed circuit board 14 a and circuit board 14 bmay be benched. Struts 80 st of assembly 80 as in module 10-1 may beformed integral with remaining components of assembly 80 or else struts80 st as shown my module 10-2 may be formed separate from assemblycomponents e.g. 81 and 82. Module 10-2 is shown as being devoid ofoptical plate 26 as is described herein. The functions provided by plate26 could be wholly or partially be provided by a member not incorporatedinto module 10-2 (such as a member of a reader housing 111), or else thefunctionality of optical plate 26 could wholly or partially beincorporated directly into light sources 16, 18 of module as will bedescribed herein.

[0102] Further variations of module 10 are shown in FIGS. 2e and 2 f. Inthe embodiment of FIG. 2e, imaging module 10-3 includes a single PCB 14a instead of first and second PCBs as shown in FIG. 1a (module 10-1) andFIG. 2a (module 10-2). Surface integrated aiming LEDs 18 andillumination LEDs 16 are mounted on the front side 14 f of PCB 14 whileprocessing circuitry, e.g. control circuit 140, or a part of thereof ismounted on a rear side 14 a-r of PCB 14 a. A support assembly 80including a containment section 81 and retainer section 82 for holdinglens barrel 40 in the embodiment of FIG. 2e can have the same generalconfiguration assembly 80 shown in FIG. 2f.

[0103] Another variation of an imaging module according to the inventionis shown in FIG. 2f. In the embodiment of module 10-4, 10 shown in FIG.2f, support posts 84 are replaced by threaded screws 84 t which arethreaded into screw holes 83 t of PCB and support assembly 80 forsecuring of the component part of module 10. It is seen further that PCB14 b having surface integrated illumination and aiming LEDs 16, 18 canbe replaced by the combination shown of a planar member 14 p which maybe a PCB having a pair of PCBs 14 b 1 and 14 b 2 back mounted thereon,wherein each of the PCBs 14 b 1 and 14 b 2 comprise surface integratedillumination LEDs 16 and surface integrated aiming LEDs 18 as aredescribed herein. Of course, any one of the surface integrated LEDsshown and described herein can be replaced by e.g. a traditional leadedLED, a surface mount LED, a side leaded, surface mount LED, as aredescribed herein.

[0104] In the embodiment of FIG. 2g, module, 10-5 like module 10-1includes an optical plate 26 mounted forward of circuit board 14 b andsupported on support posts 84. Optical plate 26 of the type included inmodule 10-5 of FIG. 2g is described in more detail herein with referenceto FIGS. 5d, 5 e, and 5 f. Optical plate 26 as shown in FIG. 2g mayinclude a plurality of substantially cylindrical microlenses andcross-connections as will be described in greater detail with referenceto FIGS. 5d-5 f. Optical plate 26 as shown in FIG. 2g can alsoincorporate therein aiming optics 25 provided by cylindrical lenses 25c. As will be described in greater detail, apertures 43 as shown forexample in FIGS. 1h, 1 q, 1 m, 6 m and 6 q may be disposed forward ofaiming LEDs 18 and lenses e.g. 25 may be configured to image lightpassing through an aperture onto a target area T so that an aiming line,or other aiming pattern is projected onto a target area, T. Opticalplate 26 in the embodiment of FIG. 2g can be replaced with an opticalplate having a separate diffuser 27 for each illumination LED as shownin module 10-1 FIG. 1a. As explained elsewhere herein (e.g FIG. 1n, FIG.2o, and FIGS. 5g-5 k) optical plate 26 can have wedges 28 formed on alight entry surface or exit surface thereof for directing light to acorner of a target area, T.

[0105] Another variation of an imaging module is shown in FIG. 2h byextending posts 84 further, as shown by module 10-6, 10 of FIG. 2hadditional members having incorporated post holes 83 can be incorporatedinto imaging module 10. For example, the optics incorporated in opticalplate 26 of e.g. module 10-1 or module 10-6 can be spread out over morethan one member. As shown by module 10-6 a first optical plate 26, 860,can carry illumination optics such as diffusers 27 and a second opticalplate 26, 862 can carry aiming optics such as cylindrical lenses 25. Aswill be explained further herein, diffusers 27 can be of any suitabletype e.g refractive optic microlens, diffractive, or negative lens.Module 10-6, in addition to including an additional front member 862stacked on module 10, includes an additional rear member 14 p.Additional rear member 14 p may be e.g. a thermally conductiveelectrically insulating member which is employed as a heat sink for usein reducing a temperature of module 10-6, or else member 14 p may bee.g. a printed circuit board for carrying additional circuit components.

[0106] Referring to further aspects of module 10-6, posts 84 of module10-6 include ring spacers 84 r. Ring spacers 84 r may be incorporatedinto posts 84, or ring spacers 84 r may comprise a plastic sleevefittable over posts 84 or else ring spacers 84 r may comprise a memberthat is snap-fit into a slot machined in posts 84 p. Ring spacers 84 raid in properly spacing stacked members of module 10. Features of theinvention relating primarily to support posts 84 of modules e.g. 10-1,10-2, 10-5, and 10-6 are now described in greater detail. Formed in eachstrut 80 st as explained with reference to module 10-1 is a support posthole 83 for accommodating a support post 84. In any of thepost-containing modules described each support post 84 may be frictionfit yet substantially slidable in its associated post hole 83. In thealternative, each support post 84 may be rigidly mounted withinassociated hole 83. Support assembly 80 may be over-molded on posts 84 pto rigidly secure posts 84 p to assembly 80. Circuit boards 14 a and 14b also have post holes 83 for accommodating support posts 84 p. Holes 14h of circuit boards 14 a and 14 b are formed in such a manner relativeto posts 84 h so that holes 14 h aid in properly aligning the variouscomponents of module 10 a-1 as will be described in further detailherein. While it is seen that struts 80 st are highly useful, it is alsoseen that struts 80 st could be eliminated in the interest of reducingthe size of module 10. In the embodiment of FIG. 1v an embodiment ofsupport 80 having integrated elongated struts 80 st is shown. Elongatedstruts 80 st may be advantageous e.g. where struts 80 st are overmoldedonto posts 84 and where it is desired to firmly secure posts 84 in fixedpositions within struts 80 st.

[0107] In one method for assembling module 10 support posts 84 areinserted in the various holes of support assembly 80 such that posts 84extend outwardly from assembly 80. Printed circuit boards 14 a and 14 bare then placed over the exposed portions of post 84 p so that postholes 83 of circuit boards 14 a and 14 b accommodate support posts 84.In one embodiment of the invention post hole 83 of image sensor-carryingcircuit board 14 a can be made substantially larger than the diameter ofpost 84. Making holes 83 of circuit board 14 b substantially larger thanpost 84 allows the position of circuit board 14 a to be finely adjustedrelative to that of support assembly 80 in the X, Y, and Z directionsprior to the securing of circuit board 14 a in a certain positionrelative to assembly 80. When holes 83 are made substantially largerthan posts 84, circuit board 14 a may be tilted or moved rotationally asit is moved in a certain position relative to assembly 80 prior to thesecuring of circuit board 14 b to assembly 80. A person assemblingmodule e.g. 10-1, 10-2, 10-5, and 10-6 may utilize a video monitor toaid in the alignment process. Module 10 can be actuated to capture animage which can be displayed on a video monitor, e.g. a host computersystem (e.g. PC) video monitor as is explained more fully in applicationSer. No. 09/954,081, entitled “Imaging Device Having Indicia-ControlledImage Parsing Mode,” filed Sep. 17, 2001 incorporated by referenceherein. The module 10 may be made to capture an image of a targetcomprising fine print indicia (e.g. a dollar bill) and a user may adjustthe components of the module that are being assembled until thedisplayed image displayed on the monitor is satisfactory. The securingof circuit board 14 a relative to assembly 80 can be accomplished withuse of solder. A further explanation of the embodiment wherein postholes 83 of circuit board 14 a are made substantially larger thansupport structures which in some limited aspects operate similarly toposts 84 is described in copending application Ser. No. 09/312,479 filedMay 17, 1999 entitled “Optical and Image Sensor Subassembly Alignmentand Mounting Method” incorporated herein by reference. Where theposition of image sensor 32 does not have to be finely adjusted relativeto lens assembly 40, post holes 83 of circuit board 14 a areconveniently sized to be friction-fit over posts 84.

[0108] Referring to further aspects of modules described hereinincluding posts 84, support posts 84 are preferably made electricallyconductive and are disposed in module 10 so that posts 84 provideelectrical communication between electrical circuit components of firstcircuit board 14 a and second circuit board 14 b. Circuit board 14 bcomprises illumination LEDs 16 and in some cases aiming LEDs 18, bothrequiring electrical power for operation. Circuit board 14 a carriesimage sensor 32, in some cases aiming LEDs 18 and certain electricalcircuitry associated with image sensor 32 as will be described laterherein. Processing circuitry associated with image sensor 32 may bemounted on face 14 a-f and/or rear 14 a-r of circuit board 14 a.Configuring module 10 so that support posts 84 both provide structuralsupport and electrical communication between circuit components of firstand second circuit boards 14 a and 14 b provide an important spaceconservation advantage and allows module 10 to be made smaller thanwould be possible if separate structural members (e.g. including flexconnectors for connection between boards 14 a and 14 b) were disposed inmodule 10 to provide the functions of structural support and electricalcommunication.

[0109] Further aspects of one type of support post which may be utilizedwith post contacting modules e.g. 10-1, 10-7 are described withreference to the exploded view of post 84 shown in FIG. 11r. Supportpost 84 in the embodiment of FIG. 1rcomprises barb 890, a step patterndefined by steps s1, s2, and s3 and head 892 having an open end 894sized so that step s3 of another one of posts 84 can be friction-fittedor slip-fitted into open end 894.

[0110] Barb 890 of post 84 allow post 84 to be friction-held in acertain position in plate 26 during assembly of module e.g. 0-1 withoutany outside securing agents such as adhesive material or solder.

[0111] The step pattern of post 84 defined by steps s1, s2, and s3eliminates the need to provide spacer elements on certain of thecomponent of module e.g. 10-1. Of course, steps e.g. s₁, s₂, and s₃ canbe utilized in combination with spacers e.g. 878 Referring to FIG. 1o,it is seen that aperture plate 610 can be benched against ridges rl2between first and second step s1 and s2. Further, it is seen withreference to FIGS. 2i-2 k, that an additional PCB 14C or other structurecan be benched against the ridges r23 of posts 84 defined between thesecond and third steps s2 and s3 posts 84 p.

[0112] It will be described later therein that PCB 14 b preferablycomprises highly integrated circuit components so that all, essentiallyall, or substantially all circuit components required in reader 110 arecarried by a single PCB, e.g. PCB 14 b. Nevertheless, in certainapplications wherein additional space is available, it may be desirable,for reducing the overall cost of the circuit components, to incorporatein reader 110 larger circuit components with a lesser degree ofintegration and to spread the circuit components over more than onemajor circuit component carrying circuit board. It will be seen thatposts 84, especially when configured as shown in FIG. 1r readilyfacilitates module configurations wherein circuit components are spreadout over several boards and wherein the module may nevertheless retain acompact generally cubical configuration. As indicated previously, anadditional circuit board 14 c may be benched against ridges r23.Furthermore the open ends 894 of additional posts 84 a may be fittedonto posts 84 and another additional circuit board e.g. PCB 14 d orboards may be fitted onto the additional posts. Because posts 84 can bemade electrically conductive the electrical communication betweenmultiple circuit boards of module 10 a can be provided by posts 84.Posts 84 therefore eliminate the need to install space consumingelectrical connectors, e.g. flex strip receptacles, on one or more ofthe circuit boards e.g. 14 a, 14 b, and 14 c of module 10, when thenumber of conductive paths required between the boards is equal to orless than the number of the posts 84.

[0113] Further aspects of the invention relating primarily to theassembly of module 10 a are described with reference to FIGS. 1o to 1 u.FIG. 1o shows an assembly diagram corresponding to module 10-7 which issimilar to module 10-1 discussed in connection with FIGS. 1a-1 g. Inmodule 10-7 apertures 43 are defined in nonintegrated aperture plate 610rather than in support assembly 80. In one method for assembling module10-7 conductive support posts 84 are first installed in plate 26 andthen assembly 870 comprising the combination PCB 14 b having attachedthereto plate 610 is applied over posts 84. Next, assembly 872comprising support assembly 80, and PCB 14 a having attached theretoLEDs 18 (shown as traditional leaded LEDs) is applied over posts 84 andposts 84 are soldered to PCB 14 a. At interfaces 885, as best seen inFIG. 1u, to secure the components of module together as a packaged unit,as will be explained in greater detail herein, solder can also beapplied at interfaces 884 between posts 84 and board 14 b to furthersecure component of module 10-7, and to provide electrical connectionbetween post 84 and board 14 b if such connection is necessary. Finally,lens assembly 40 provided by a lens barrel is inserted into retainersection 82 of assembly 80, precision adjusted, and secured to retainersection 82 in a manner that will be described more fully herein below.It will be seen that the assembly process for assembling module 10-1 canbe substantially the same except that the combination of plate 26 andposts 84 can be fitted onto PCB 14 b rather than the assembly comprisingPCB 14 b and aperture plate 610.

[0114] Referring to further aspects of module 10-7, module 10-7 likemodule 10-1 includes a plurality of discreet diffuser patterns 27 onoptical plate 26 rather than a single diffuser pattern as is shown bymodule 10-5 in the embodiment of FIG. 2g. Further, it is seen that inmodule 10-7 as in module 10-5 and module 10-1 the plane of the mostforward surface of plate 26 is positioned forwardly of the plane definedby the exit surfaces of aimer optics 25. The positioning of optics 25 onplate 26 so that the plane defined by diffusers 27 is forward of theplane defined by optics 25, protects optics 25 from damage which may becaused by incidental or accidental contact of module 10-1, 10 a-7 withvarious objects during use or installation of module 10 into a readerhousing. It is useful to design plate 26-1 so that it is more likelythat optics 27 come in contact than optics 25 since the illuminationsystem of module 10 is less sensitive to imperfections in optics 27 thanis the aiming system of module 10 to imperfections in optics 25.

[0115] Alternative module components which may be incorporated in any ofmodules e.g. modules 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, and 10-7 aredescribed with reference to FIGS. 1p and 1 q. In the partially assembledmodule of FIG. 1p support assembly 80 comprises LED holders 876. LEDholders 876 hold LEDs 18 in position during the assembly process so thatLEDS 18 do not have to be soldered to PCB 14 a prior to PCB 14 a beingattached to posts 84. That is, without LEDs 18 being soldered to PCB 14a, an assembler may hold the combination of support assembly 80, LEDs18, and PCB 14 a together with his hand during the assembly process,place the combination of these parts over posts 84, and in one solderingstep solder both of LEDs 18 to posts 84 to PCB 14 a to secure themodule's component together. In a further aspect of support assembly 80shown in FIGS. 1p and 1 s, retainer assembly 80 includes spacers 878 and880. Spacers 878 of assembly 80 provide spacing between support 80 andPCB 14 b. Spacers 880 (only one seen) includes an integrated key pin formatingly engaging key hole 882 of PCB 14 b. Use of spacers 878, 880, and846, 848 (module 10-1) to provide spacing between support assembly 80and PCB 14 b rather than post hole containing struts 80 st results in anexposed interface 884 between posts 84 and the rear surface 14 b-r ofPCB 14 b being defined as best seen in FIG. 1u. Solder can be applied atthese interfaces 884 during the assembly of module e.g 10-1, 10-7 toreinforce the mechanical holding forces holding together the componentsof module e.g. 10-1, 10-7 and to reinforce the electrical contactbetween PCB 14 b and posts 84. In the embodiment of FIG. 1o, aiming LEDs18 are provided by traditional leaded LEDs while illumination LEDs 16are provided by side-leaded surface mounted and back benched LEDs aswill be explained more fully hereinbelow.

[0116]FIG. 1q shows an alternative embodiment of aperture plate 610.Aperture plate 610 shown in FIG. 1q is a two-piece assembly comprisingplate section 612 and aperture insert section 614. Plate section 612includes a form recess 616 of a form adapted to align and receiveaperture section 614 in a desired position within module 10 so that adesired aiming pattern is projected by module 10. Aperture section 614is received in recess 616 and secured in a position therein via anadhesive and/or friction forces. Aperture insert section 614 preferablycomprises metal. The selection of metal as the material for use informing section 614 enables apertures 43 a, 43 b, and 43 c to be made insubstantially small sizes and in sizes and shapes that can be tightlycontrolled. Aperture plate 610 in both FIGS. 1 and 1q includes keystructures 886 for engaging key structures 882 of PCB 14 b.

[0117] Reference is now made to module 10-8, shown in FIG. 2L. AimingLEDs 18 of module 10-8 have a substantially smaller height dimensionthan LEDs 18 of module 10-9 (which are leaded LEDs). Accordingly,because it is normally preferred to position aperture 43 as close as isphysically possibly to aiming light source 18, aperture 43 in theembodiment of FIG. 2L should be positioned closer to PCB 14 a thanaperture 43 of module 10-7. For positioning of an aiming aperture closerto the surface of PCB 14 a apertures 43 may be provided on supportassembly 80 as is indicated in the embodiment of retainer assembly 80shown by module 10-8 in FIGS. 2L and module 10-1 (FIG. 1h). In theembodiment of FIG. 2L, shrouds 80 sh extend forwardly from apertures 43.Shrouds 80 sh may be sized to the height of spacers 80 sp to reinforcethe spacing function provided by spacers 80 sp.

[0118] Another embodiment of an imaging module according to theinvention is shown in FIGS. 2m-2 p. Like module 10-1, imaging module10-9 is specifically designed for use in an imaging device such as a barcode reader, an optical character recognition (OCR) reader, a readerhaving both bar code and OCR reading capabilities, personal dataassistant, a video camera, a digital camera, a cellular phone, or amedical viewing instrument.

[0119] Unlike e.g. module 10-1 which includes support posts 84 forsupporting components of module 10 module 10-9 includes a mounting frame12 which is adapted to receive both electrical components and opticalcomponents of an imaging system. Mounting frame 12 is part of one pieceintegrated support assembly 80 of module 10-9 which further includescontainment section 81 and retainer section 82. Mounting frame 12receives a circuit board, such as a printed circuit board (PCB) 14 a,illumination LEDs 16, aiming LEDs 18, aperture plate 610 and opticalplate 26.

[0120] More specifically, frame 12 of support assembly includes a backplate 30 and sidewalls including top sidewalls 31 and side sidewalls31′. Back plate 30 includes a recessed containment section 81 forreceiving a solid state image sensor chip 32 and a plurality of pinholes 36 for receiving leads 38 of illumination and/or aiming lightsources, provided by leaded LEDs 16 and 18. Support assembly 80 furtherincludes a retainer section 82 formed integral with back plate 30 forreceiving a receive optics lens assembly 40, e.g. a lens barrel, whichmay be installed in retainer section 82 prior to or after any step inthe assembly process as described in greater detail below.

[0121] In assembling the module 10-9, PCB 14 a is first mounted to backplate 30 using screws 56 and frame 12 is oriented so that an opening 13is exposed. When PCB 14 a is mounted to back plate 30 the image sensor32 carried by PCB 14 a is received by center recess containment section81 which is shaped complimentary with the shape of image sensor 32 asshown. After mounting PCB 14 a to frame 12, an assembler mountsillumination LEDs 16 and aiming LEDs 18 to PCB 14 a.

[0122] To mount LEDs 16 and 18 to PCB 14 a, the leads 38 of LEDs 16 and18 are pushed through aligned pin holes 36 and 54 of back plate 30 andPCB 14 a, then the LEDs 16 and 18 are soldered to PCB 14 a. Preferably,all of the LEDs 16 and 18 are positioned in their respective pin holesbefore soldering. In soldering LEDs 16 and 18, the rear surface 14 a-rof PCB 14 a should be oriented for easy access by an assembler. To theend that LEDs 16 and 18 remain in a desired orientation which issubstantially normal to PCB 14 a during soldering, a standardly knownfixture (not shown) shaped to receive LEDs 16 and 18 can be temporarilyapplied over LEDs 16 and 18 through the soldering process.

[0123] An important feature of imaging module 10-9 is that leads 38 ofthe illumination LEDs 16 are installed in a nearly abutting relation tosides 32 s of image sensor 32 such that a portion of rear surfaces 19 ofLEDs 16 oppose a portion of a front surface 32 f of image sensor 32 whenthe LEDs 16 are completely installed. This arrangement reduces the sizeof the imaging module 12, enabling installation in smaller sized opticalreaders.

[0124] After LEDs 16 and 18 are mounted onto PCB 14 in the mannerdescribed above, the aperture plate 610 is mounted into the frame 12,the plate having domes 42 which fit over the aiming LEDs 18. The domesare preferably opaque to substantially block all light emanating fromaiming LEDs 18, except light exiting the domes through slit apertures43. Slit apertures 43 should be formed so that a desired shaped aimingpattern of illumination is projected onto a target, T. In oneembodiment, aperture slits 43 are shaped rectangularly so that ahorizontal line pattern is projected onto a target.

[0125] Aperture plate 610 further includes a number of cutaway sections46 providing clearance to allow the aperture plate to be fitted over theillumination LEDs 16. The domes 42 and cutaway sections 46 may be formedso they do not contact LEDs 16. In the embodiment shown, each LED isheld in a desired orientation while being soldered, so that the flatsurfaces of LED bases 17 are biased against the flat surface of backplate 30 during the assembly process. In a further aspect, apertureplate 610 includes a shroud 58 for preventing light transmitted by theLEDs 16 and 18 from interfering with the receive optical systems of themodule, it is seen that shroud 58 may be configured for aiming inachieving proper spacing between back plate 30 and optical plate 26.

[0126] After aperture plate 610 is placed over LEDs 16 and 18 and movedtoward back plate 30, an optical plate 26 is snap-fitted into theopening 13 of the frame 12. Optical plate 26 includes diffusers 27 fordiffusing light emanating from the illumination LEDs. In addition tohaving diffusers 27 formed on a front surface thereof optical plate 26may further have wedges 28 formed on an inner surface thereof. Wedges 28direct light from LEDs 16 toward corners of a target T so as to improvethe uniformity of a target's illumination. As will be described infurther detail, diffusers 27 can take on a variety of forms and can beformed on light entry surface of plate 26. Further wedges 28 can beformed on a light exit surface of plate 26.

[0127] Resilient fingers 48 having hook ends 49 are formed in the top orside sidewalls 31 of frame 12 to enable snap-fitting of the opticalplate 26 onto frame 12. In the embodiment shown, the optical plate 26may be snap-fitted onto the frame 12 by pulling back the resilientfingers 48, pushing the optical plate toward the back plate 30, thenreleasing the fingers 48 to lock plate 26 in position inside module 10.The plate and fingers may be formed so that the fingers are spread apartand released by plate 26 when optical plate 26 is pushed toward backplate 30. Fully assembled, module 10-9 may have a height dimension ofabout 19 mm 0.75 inches), a width dimension of about 39 mm (1.5 inches),and a depth dimension of about 27 mm (1.06 inches).

[0128] To the end that essentially the entirety of the requiredelectronic circuitry of an optical reader can be packaged into a singleprinted circuit board, the back surface of the frame's back plate 30 maybe configured to accommodate electrical components that will extendforward from the front surface 14 a-f of PCB 14 a. Accordingly, it isseen that the rear surface of back plate 30 includes a central recess 34for aligning and receiving solid state image sensor 32 and peripheralrecesses 35 for accommodating electrical circuitry 802 such ascomponents and/or conductors which may protrude from the front surfaceof PCB 14 a. The aperture plate 610 includes spacers 52 which operate tobias aperture plate 24 toward back plate 30 when optical plate 26 issnap fitted onto frame 12. The spacers 52 of module 10-9 furthertransfer the force imparted by fingers 48 on optical plate 26 to theaperture plate 610, securing both the aperture plate 610 and opticalplate 26 inside frame 12 without the use of adhesives or outsidemechanical securing means, such as screws or pins. In the embodiment ofFIG. 2n optical plate 26 includes a separate diffuser 27 for eachillumination LED 16. In the alternative embodiment of FIG. 5d a singlediffuser 27 is formed substantially throughout the surface of plate 26.

[0129] Referring to further variations of module 10, in the embodimentof FIGS. 3a-3 d imaging module 10-10 includes a printed circuit board 14a having both an image sensor 32 and illumination LEDs 16 mountedthereon. A pair of LEDs are mounted on either side of image sensor 32 toform a pattern of LEDs comprising four substantially linearly arrangedLEDs. Mounting of LEDs in a horizontally oriented linear pattern reducesthe height dimension requirements of module 10-10 relative to that ofmodule 10-9 and module 10-1. Mounting of LEDs in a horizontally orientedlinear pattern allows the height of module 10-2 to be reduced to aheight closer to the height of image sensor 32. Referring to furtheraspects of module 10-10, module 10-10 includes a support assembly 80mounted to and extending from PCB 14. Support assembly 80 in each of theembodiments shown of FIGS. 3a-4 d and 4 k-4 n includes a containmentsection 81 and a retainer section 82. Containment section 81 containsimage sensor 32 while retainer section 82 retains lens assembly 40.Retainer 82 also prevents light rays not corresponding to the image at atarget, notably rays emanating directly from LEDs 16 from reaching imagesensor 32.

[0130] Referring to further variations of an imaging module according tothe invention, in the embodiment of FIGS. 3e-3 h imaging module 10-11includes a printed circuit board 14 a having mounted thereon an imagesensor chip 32, illumination LEDs 16, and aiming LEDs 18. Three LEDs aremounted on either side of module 10-11 to form a horizontally orientedsubstantially linear pattern of LEDs comprising six LEDs. Inner LEDs 18are aiming LEDs while outer LEDs 16 are illumination LEDs. IlluminationLEDs 16 may be canted (mounted at angles) as best seen in FIG. 3h sothat a center of a target area is more uniformly illuminated absentadditional illumination optics.

[0131] Further variations of imaging modules are shown in FIGS. 3i-3 m.In module 10-12 of FIG. 3i the configuration of support assembly 80 ismodified so that assembly 80 is box shaped and of substantially uniformheight, width and depth. Box-shaped containment and retainer assembly80, particularly when sized to a height substantially equally to that ofcircuit board 14 provides certain packaging advantages. For example, ifmodule 10-12 is mounted in an instrument housing so that assembly 80abuts on a planar surface of an instrument housing, box shaped assembly80 aids in the stabilization of module 10-12. Module 10-13 shown in FIG.3j comprises a configuration essentially identical to module 10-12except that the leaded LEDs are replaced with surface mounted LEDs 16and 18 as shown. It is understood that the leaded LEDs described hereincan normally be replaced with surface mounted LEDs as seen in FIG. 3j,side-leaded surface mounted LED, or surface integrated LEDs.

[0132] Modules 10-10, 10-11, 10-12 and 10-13 may be used in combinationwith illumination optics mounted to a separate member of an instrumenthousing 111. Alternatively, illumination optics can be incorporated intothe module as illustrated by modules 10-14, 10-15 and 10-16 of FIGS. 3k,3L, and 3 m. Module 10-14 of FIG. 3k includes form fit diffusers 504, 27which are adapted to be friction-fit over illumination LEDs 16. In theembodiments shown in FIGS. 3L and 3m module 10-15, 10-16 includesoptical flanges 803 extending outwardly from assembly 80. Each flange803 may include slit aperture 43 for shaping light from aiming LEDs 18and a diffuser 27 for diffusing light from illumination LEDs 16.Diffusers 27 may be molded into flanges 803 as part of plate inserts560. Flanges 803 may be formed integral with support assembly 80 using amold adapted for manufacture of a one piece containment, retainer andflange assembly. Flanges 84 may also be mounted to PCB 14 a or to amember of the instrument housing in which the module is installed.Module 10-16 shown in FIG. 3m is similar to module 10-15 except thatleaded LEDs are replaced with surface mounted LEDs 16 and 18 as shown.In addition, flanges 803 of module 10-16 are spaced apart at a closerdistance to PCB 14 a than flanges 803 of module 10-15.

[0133] Diffusers 27 of module 10-15 are shown as being of the typeincluding horizontally oriented substantially cylindrical microlensesformed on a light exit surface of the optical member including diffusers27. As will be described in greater detail herein, substantiallycylindrical microlenses operate to diffuse light preferentiallytransversely to the orientation of the microlenses. Thus horizontallyoriented microlenses of diffusers 27 of module 10-15, having linearlyarranged illumination LEDs 16 will operate to increase the heightdimension of the overall illumination pattern generated using a linearlyarranged set of light sources.

[0134] Another imaging module is shown in FIGS. 4a-4 d. In module 10-17,a flexible printed circuit board 14 a carries an image sensor chip 32and a light pipe 310 for transmitting light from a source location 312to a light pipe distal end 314 remote from the source location. Lightpipe 310 of module 10-17 is shown as being provided by a fiber opticcable. However, light pipes may also be molded light pipes. Fiber opticcables are available from several manufacturers including Schott Corp.of Wayzata, Minn. and Bivaropto, Inc. of Irvine, Calif. Light pipes 310can be any length and can be mounted at substantially any location offlexible circuit board 14 a of module 10-17. It will be appreciated thatthe configuration of module 10-17 allows installation of module 10-17into a wide variety of instrument housings and equipment. Flexiblecircuit board 14 a of module 10-17 which may be a type available fromMinco, Inc. of Minneapolis, Minn., may be bended into a virtuallylimitless number of forms to allow installation of module 10-17 intoinstrument housings of a wide variety of shapes and sizes. Furthermore,light pipe 310 provides illumination of a target area T when distal ends314 are directed to a target without requiring that space consuming LEDsbe mounted in a certain arrangement about an imaging axis. An importantadvantage of incorporating light pipe 310 into an imaging module 10-17is that the radiance of illumination emitted by an individual light pipecan be increased without increasing the space consumed by the distal end314 of the individual light pipe. The radiance of light emitted at adistal end 314 of a light pipe can be increased by directing light frommore than one source into a source end 312 of the light pipe. A sourceend of a light pipe can be split into two or more light entry units 312a and 312 b as shown by FIG. 4e, each of which is disposed in proximitywith a light source such as an LED. Also, a light pipe can be made tohave a large source end and diameter enabling it to receive light frommore than one light source as shown by FIGS. 4f, 4 i and 4 j.

[0135] Now referring to FIGS. 4g-4 j an imaging module 10-18 isdescribed having molded light pipes 311. In module 10-18, PCB 14 a isarranged parallel to imaging axis, a₁, and image sensor chip 32 ismounted perpendicularly on PCB 14 a. Image sensor 32 may beperpendicularly mounted on PCB 14 a by using a rigid flex PCB. Referringto further aspects of module 10-18, LEDs 16, and 18 provided by surfacemount type LEDs are mounted on PCB 14 a and molded light pipes aredisposed in relation to LEDs 16 s and 18 s so that light from LEDs 16and 18 is directed through distal ends 314 of light pipes in a directiongenerally parallel to imaging axis, a_(i), toward a target T. Moldedlight pipes 311 are available from such manufacturers as Bivaropto, Inc.of Irvine Calif. and Dialight Corp. of Manasquan, N.J. Diffusers can bemolded onto the distal ends of illumination light pipes 311, 311 i as isindicated by diffusers 27 shown in FIG. 4g. Diffusers can be e.g.diffractive optic, refractive optic (e.g. microlens), or negative lensdiffusers. Diffusers can also be formed at distal ends 314 of pipes 310of module 10-17. As in the case of a fiber optic cable light pipe, theradiance of illumination emitted by any one molded light pipe 311 can beincreased by widening source end 312 of pipe 311 and disposing sourceend 311 to collect light from more than one light source, as isindicated by light pipes 311 i of FIG. 4g. Illumination light pipe 311 iof module 10-18 shown in FIG. 4j collects light from three surfacemounted LEDs 16 whereas aiming light pipe 311 a collects light from asingle surface mount LED 18.

[0136] Arranging PCB 14 a parallel to imaging axis, a_(i), andinstalling molded light pipe 311 on PCB 14 a to direct light in adirection parallel to PCB 14 a reduces the height dimension of module 10and facilitates installation of the module to in a “thin” instrumenthousing having a small height dimension. The height dimension of animaging module 10 having light pipe illumination can be reduced furtherby back mounting of image sensor chip 32 on PCB 14 a as is illustratedby module 10-19 shown in FIGS. 4k-4 n. In the embodiment of FIGS. 4k-4 nimage sensor chip 32 is back mounted on PCB 14 a together with acontainment and retainer assembly 80 that is equipped with foldingoptics sufficient to fold imaging axis, a_(i), substantially 90 degrees.Folding optics can be provided, for example, by formation of platedreflective material on or by affixing a mirror to wall 402 as indicatedby dashed-in mirror 404. Because module 10-19 can be designed to have aheight dimension smaller than the width of image sensor 32, module 10-19is especially well-suited for installation in “thin” reader housings.For example, module 10-14 is well suited for installation into thehousings of a personal data assistant “PDA” such as a cellular phone asshown in FIG. 9i, or a hand-held computer as shown in FIG. 9j.

[0137] B. Illumination

[0138] Features of illumination systems in accordance with the inventionare now described primarily with reference to FIGS. 5a-5 f. Forsubstantially uniform illumination of a target area T in an overallpattern 520 corresponding to the field of view of image sensor 32 (inwhich corners are illuminated to a brightness of at least about 50% ofthe target areas maximum brightness), light emanating from each LED in atwo row, four LED illumination system (as in e.g. module 10-1 or module10-9) should be diffused to provide a substantially rectangularillumination pattern having borders 19 substantially defined by lines522 as is shown in FIG. 5a.

[0139] Shown in FIG. 5b is a surface of a mold 526 for use inmanufacturing a multiple diffuser optical plate 26 e.g. of module 10-9(FIG. 2n), mold 526 may have installed therein separately manufactureddiffractive mold elements 528. Mold element 528 installed in mold 526may be of the type manufactured using holographic techniques as areavailable from Physical Optics Corp. of Torrance, Calif. and FresnelOptics of Rochester, N.Y. Other manufactures of diffuser opticalelements include DOC of Charlotte, N.C., MEMS of Huntsville, Ala. andRPC of Rochester, N.Y.

[0140] Shown in FIG. 5c is a surface of a mold 527 for use inmanufacturing a single diffuser optical plate 26 as is incorporated ine.g. module 10-5 of FIG. 2g and as shown by plate 26 of FIG. 5d. Mold527 includes a texture formed directly thereon. The texture may beapplied by way of an acid resist process. Mold texturing companies, suchas Mold Tech, Inc. of Painsville, Ohio specialize in applying texturesto molds by way of an acid resist process as in old 527 used to make apart having a surface having the texture shown in FIG. 5e. A suitablematerial for use in the manufacture of optical plate 26 in any of theembodiments described herein is polycarbonate.

[0141] The textured surface mold 527 of FIG. 2p is generally lessexpensive and more durable than the mold having installed diffractivediffuser mold element inserts 528 of FIG. 5b. Diffractive mold element528 is costly to manufacture, and requires frequent replacement.Textured molds as shown in FIG. 5c are typically used in applicationssuch as manufacturing fingerprint-resistant surfaces. As far as isknown, light transmissive plates made using insertless textured surfacemolds as shown in FIG. 5c have been incorporated in products havinglight sources primarily for the purpose of obscuring the view of a lightsource, and have not been used to produce controlled target areaillumination of an image capture system.

[0142] Exploded views of the diffuser surface of optical plate 26 ofFIG. 5d having a single diffuser 27 for diffusing light from severalLEDs are shown in FIGS. 5e and 5 f. Plate 26 comprises a plurality ofsubstantially adjacent and substantially cylindrical microlenses 550.Referring to further aspects of microlenses 550, microlenses 550 arepreferably formed in randomized pattern on plate 26 characterized inthat microlenses 550 comprise at least two different sizes without aparticular ordering of similar-sized microlenses and without preciseparallel relative orientation between the lenses. Randomization of thepattern reduces the formation of “hot spots,” concentrated areas ofconstant higher radiance illumination, on a target area T. In anotheraspect of plate 26, plate 26 as shown in FIG. 5d preferably comprisesoccasional cross-connections 552 defined in the valleys 554 delimitingthe various cylindrical microlenses 550. Cross-connections 552 providediffusion of light in a direction generally transverse to the directionof light diffusion provided by microlenses 550 microlenses 550 arebelieved to operate by converging light rays from sources 16 intoconvergence points positioned closely forward of lenses 550, such thatthe rays are in diverging relation to another at typical module totarget reading distances (e.g. about 1 inch to 15 inches for commoncodes).

[0143] Referring to FIG. 2q, the diffused light pattern generated by asingle light source as diffused by single diffuser optical plate 26shown by FIG. 5d is designated as the pattern substantially determinedby border lines 522 of the overall illumination pattern substantiallydelimited by border 520. Vertically oriented cylindrical microlenses 550tend to diffuse light in a horizontal direction while the lensingprovided by cross-connections 552 tend to diffuse light from a lightsource in a vertical direction. It can be seen that diffusion patternscan be controlled by appropriate shaping of microlenses 550. Reducingthe incidence of cross-connections 552 would reduce the diffusion oflight in the vertical direction. With a reduced incidence of crossconnections an illumination pattern corresponding to a single lightsource substantially delimited by dashed line 521 may be generated.Increasing the incidence of cross-connections 552 would increase thediffusion of light in the vertical direction. An increased incidence ofcross connections 552 might generate the illumination pattern for asingle light source delimited substantially by dashed lines 523. Adiffuser comprising a series of spherical refractive optic microlenseswould be expected to generate a substantially uniform circularillumination pattern which may be highly desirable depending on theintended applications and overall design of the module. Diffusing lightin a vertical direction to increase the height of an illuminationpattern is particularly useful in the case that a target illuminationdiffuser is incorporated in an imaging module having a single row ofhorizontally oriented light sources and incorporates a 2D image sensor.Referring again to FIG. 3L, module 10-15 comprises plate inserts 560including diffusers 27 comprising horizontally oriented cylindricalmicrolenses 550. Microlenses 550 of module 10-15 diffuse lightvertically with respect to the horizontal axes h of module 10-15 therebyincreasing the vertical (height) dimension of the illumination patternprojected by modules 10-15. Microlenses 550 of plate 26 or plate inserts560 may not be formed in a randomized pattern and may not comprisecross-connections 552. Nevertheless, cylindrical microlenses 550 ofplate 26 described with reference to FIG. 5e operate to diffuse light ina direction generally perpendicular to microlenses 550. Plate insert 550of module 10-15 could be replaced with a plate similar to plate 26 ofFIG. 5d having randomized pattern of microlenses and being modified toinclude cylindrical microlenses oriented horizontally rather thanvertically. Optical plate 26 e.g. plate 26 of FIG. formed with use ofsubstantially uniformly textured mold 527, diffuses light substantiallyvia refractive optics. By contrast, optical plate 26 shown e.g. inmodule 10-9 made using a mold e.g. mold 526 having holographic formedinserts diffuses light substantially via diffractive optics. Configuringoptical plate 26 to diffuse light substantially via refractive optics asopposed to substantially via diffractive optics is advantageous at leastfor the reason that molds used to make refractive optic diffusers areeasier to make and less expensive, while being substantially moredurable than molds used to make diffractive optic diffusers. As is knownby skilled artisans, diffractive optical characteristics predominatewhen optical elements transmitting light are in a range of sizesproximate the wavelength of light being transmitted. Several imagingmodules described herein include light sources that emit light in thewavelength range of from about 0.4 to about 1.0 microns. For refractivediffusing of light in this wavelength range the optical elements of adiffuser should have dimensions substantially larger than the upperlimit of this range, e.g. at least about 10 microns. For example, asbest seen in cross sectional view of FIG. 5f, cylindrical microlenses550 of optical plate 26 of FIGS. 5d, 5 e, and e.g modules 10-5 and 10-9may have an apex-to-apex separation that ranges from about 0.018 inchesto about 0.028 inches.

[0144] Referring to further aspects of optical plate 26, it will beunderstood that optical plate 26 can be made using a mold havingdiffuser section mold inserts similar to inserts 528, wherein theinserts include a microlens-forming texture as in mold 57. Providing amold similar to mold 526 except having microlens forming mold insertsinstead of diffractive diffuser mold inserts 528 facilitates the costadvantages of utilizing mold 527 and other advantages. New mold insertscan be interchanged into the mold to replace a worn mold insert or tosatisfy a special customer request for example. Mold inserts can bemanufactured in accordance with the texturing process as described inconnection with FIG. 5c or else mold inserts can be machined from metalmembers using a standard metal machining process. As indicatedpreviously microlenses made from a mold can be cylindrical or spherical,can include or be substantially devoid of corse connections 552 and canhave uniform or nonuniform apex to apex distances. Modules 10-1, 10-7,10-8 are examples of modules including optical plates 26 manufacturedusing a mold comprising a plurality of microlens-forming mold inserts.

[0145] In addition to having at least one diffuser 27, optical plates 26described herein for use with modules e.g. module 10-1 and module 10-9include wedges 28 formed on light entry surfaced thereof as shown byFIG. in (relating to module 10-1) and FIG. 20 (relating to module 10-9).Wedges 28 operate to direct light from illumination light sources 16toward corners of a target area e.g. target area 520 as shown in FIG.5a.

[0146] Diffusers 27 as shown in the various imaging modules can beprovided in a number of varieties. Examples of optical plates 26 havevarying types of diffusers are described with reference to FIGS. 5gthrough 5 k showing a top view of optical plate 26 in variousembodiments taken a long a row of illumination LEDs 16. In theembodiment of FIG. 5g optical plate 26 includes diffractive opticdiffusers 27, 27 a as shown e.g. by module 10-9. In the embodiment ofFIG. 5h, optical plate 26 includes refractive optic microlens diffusers27, 27 b as shown e.g. by module 10-1. In the embodiment of FIG. 5i,optical plate 26 comprises negative lens diffusers 27, 27 c. Negativelens diffusers are provided by forming negative lens (generally concave)lens surfaces on plate 26. With use of a negative lens to provide adiffusion function, light rays generated by sources 16 are in divergingrelation to one another when exiting light exit surface 566 plate 26.Negative lens diffuser 27 c as seen from a top view in FIGS. 5i, 5 j,and 5 k can be a spherical negative lens or a vertically orientedcylindrical lens. If negative lens diffuser 27 c is a verticallyoriented cylindrical lens, diffuser 27 will tend to diffuse lighthorizontally. If negative lens 27 c is spherical it will tend to diffuselight both vertically and horizontally. It may also be desirable toinclude in one of the modules 10 described herein a horizontallydisposed cylindrical negative lens diffuser 27 c which diffuses lightvertically. FIG. 5L shows a functional partial side view a modifiedversion of module 10-15 (FIG. 3L) including a single row of LEDs andflanges 803, which hold optical plate inserts 560 at positions forwardof LEDs. In the variation of module 10-15 shown in FIG. 5L it is seenthat refractive optic microlens diffusers 27 of module 10-15 cancomprise horizontally oriented cylindrical negative lens diffusers 27 cfor diffusing light vertically. While negative lens surfaces 27 c areshown as being provided on both the light entry and light exit sides ofplate 560 it is understood that negative lens surfaces could be providedon just one of the light entry and light exit surfaces shown in FIG. 5L.

[0147] Referring again to the variations of optical plates 26 shown inFIGS. 5g through 5 k, FIG. 5i illustrates that diffusers 27 need not beformed on a light exit surface of plate 26. Plate 26 of FIG. 5i furtherdemonstrates that a surface of plate 26 can comprise a combination ofoptical elements. In plate 26 of FIG. 5i, surface 567 comprises anegative lens diffuser surface 27 c superimposed on a wedge 28 lightentry surface. Surface 568 of plate 26 shown in FIG. 5i comprises amicrolens diffuser surface 27 b superimposed on a wedge 28. Opticalplate 26 of FIG. 5i further comprises a wedge 28 formed on a light exitsurface of optical plate. Referring to optical plate 26 of FIG. 5k, theembodiment of FIG. 5k demonstrates that diffusers 27 can be formed onboth of light entry and light exit surfaces of plate 26. Optical plate26 of FIG. 5k includes a negative lens diffuser surfaces 27 c formed onboth of light exit 566 and light entry surfaces 565 of plate 26.Negative lenses 27 c shown in FIG. 5k can be cylindrical or sphericalnegative lens. In one embodiment, all negative lenses 27 c of FIG. 5kare spherical. In another embodiment they are all cylindrical. In yetanother embodiment negative lenses 27 c on light exit surface 566 ofplate 26 are vertically oriented cylindrical negative lenses and lenses27 c on light entry surface 565 of plate 26 are spherical negativelenses. In another embodiment spherical negative lenses are disposed onlight exit surface 566 of plate 26 and cylindrical negative lenses 27 care disposed on light entry surface 565. Any one of plates 26 describedwith reference to FIGS. 5g-5 k can be incorporated in any one of modules10 described herein including an optical plate 26. Further diffusers 27of e.g. module 10-14, 10-19 can be of any of the varieties described.

[0148] C. Aiming Systems

[0149] An aiming pattern generating system is described herein whereinan aiming optics element 25 is disposed forward of an aiming aperture 43to image light rays emanating from the aiming aperture. Severalvariations of aiming pattern generating systems according to theinvention are now described.

[0150] For providing an aiming pattern that is clear and sharp it isnormally preferred that a substantial distance is provided betweenoptics 25 and aiming aperture 43. For example, if aiming optics 25includes imaging optics, slit 43 should be disposed behind a back focalpoint of optics 25. In module 10, 10-20 (FIG. 6a) and module 10-1 (FIG.1a) a substantial distance between aperture 43 and optics 25 is providedby mounting aiming LEDs 18 on circuit board 14 a rather than on circuitboard 14 b. Aiming LEDs 18 of module 10-20, shown as being provided bytraditional leaded LEDs, are conveniently mounted on circuit board 14 ain a position such that they are located horizontally laterally relativeto retainer section 82 of support 80.

[0151] Further, with reference to module 10-20, aiming apertures 43 aredisposed in a cluster formation by way of aperture 43 a, 43 b, and 43 cso that a two-dimensional image is projected onto target T by thecombination of aiming LED, aperture cluster comprising apertures 43 a,43 b, 43 c, and optics 25. With reference to optics 25, it is seen thataiming optics 25 of module 10-20 comprises spherical lens 25 s ratherthan a cylindrical lens. Apertures 43 of module 10-20, like apertures 43of e.g. module 10-1, 10-7, 10-8, 10-9, 10-15, 10-16, and 10-22 areformed in abutting or nearly abutting relation relative to light source18. Apertures 43 a, 43 b, and 43 c are therefore imaged in thehorizontal and vertical directions onto a target T by optics 25.Aperture cluster comprising apertures 43 a, 43 b, and 43 c can belaterally offset relative to lens 25 s, so that the pattern imaged bylens 25 s moves laterally inward toward a center of a target T as module10-20 is moved closer to a Target, T. It is seen that providingsymmetrical aiming pattern generating subsystems on either side ofmodule, wherein there is lateral offset between aperture clusters 43 a,43 b, and 43 c and lenses 25 s results in the pair of patterns projectedby the pair of illuminations systems converging at a certainmodule-to-target distance. The aiming pattern generating system can bedesigned so that the pair of aiming patterns converge at the best focusposition of module 10. With reference to further aspect of module 10-20,module 10-20 like module 10-7 includes aperture plate 610. Apertureplate 610 is disposed on PCB 14 b. Plate 610 includes lead holes 620 foraccommodating leads of illumination LEDs 16 and apertures 43, asdiscussed previously. Plate 610 should be opaque at least in the area ofapertures 43 a, 43 b, and 43 c. In the variation of plate 610 shown inFIG. 6d, plate 610 includes a metal aperture insert 614 for precisiondefining of small-sized apertures. Module 10-20 further includes arefractive optic diffuser plate 26 comprising substantially cylindricalmicrolenses as described previously in connection with FIG. 5e. Module10-20 further evidenced that support posts 84 are advantageous for thepurposes of accommodating a stacked-up configuration for module 10 whichincludes a plurality of plate-like members such as PCB 14 a, PCB 14 b,plate 610 and optical plate 26. Refer now to aspects of module 10-20spherical lens aiming optics 25 s could be replaced with cylindricallenses 25 c or other optical elements for imaging apertures 43 onto atarget area T.

[0152] Representations of other exemplary illumination and aimingillumination patterns which may be projected by the illumination systemof modules 10 described herein are shown in FIGS. 6h-6 j. In FIG. 6h,area delimited by border 520 represents the region relative to a targetarea T illuminated by illumination LEDs 16 while area 630 represents theregion of the target area highlighted by aiming LEDs 18 and theirassociated optics. In the embodiment of FIG. 6h aiming LEDs 18 and theirassociated optics (43, 25) project a solitary horizontal aiming line 630onto a target area T.

[0153] The straight line aiming pattern of FIG. 6h, in one embodimentmay be generated by manufacturing plate 26 so that horizontally orientedcylindrical lenses 25, 25 c are formed on the outer surface of opticalplate 26 as is shown in module 10-9 of FIG. 2n. Horizontally orientedcylindrical lenses 25, 25 c are configured so that when plate 26 isapplied over LEDs 18 lenses 25 are aligned coextensively and forwardlyrelative to slit apertures 43 in order to image light slit apertures 43onto a target T, defined by a module's field of view. Cylindrical lenses25 may have a thickness of about 3 mm and a radius of curvature of about4.5 mm, convex. While lenses 25 are preferably of a type which convergeand thereby image light rays passing through aperture 43, it will beseen that an acceptable aiming pattern may also be projected with use ofoptics which substantially collimate light rays passing through aperture43 or which include other elements which operate to define a crisp sharppattern as will be described herein. A straight line aiming patternillustrated by line 630 or FIG. 6h can also be generated with sphericallenses 25 s and slit aperture 43 as shown in module 10-1. Methods forprojecting crisp, well-defined aiming lines over large reading distanceswill be described herein.

[0154] In modules e.g. 10-1, 10-9 and in the illumination systemdescribed in copending U.S. patent application Ser. No. 09/658,811,filed Sep. 11, 2000, entitled “Optical Assembly for Barcode Scanner” andincorporated herein by reference (module 10-22), aiming LEDs 18 projectunfolded light rays into a target area and are oriented in a directionthat is substantially parallel to the imaging axis a_(i) of module 10-1at the light entry le position of module 10-1 (the imaging axis a_(i) ofmodules e.g. 10-1, 10-9, and 10-22 is unidirectional). In module 10-22,lens 25 images a slit aperture 43 into bar code space, there beingprovided two LEDs 18 per aperture 43.

[0155] However, as is indicated by modules 10-17, 10-18 and 10-19 lightrays of aiming LEDs 18 and illumination LEDs 16 can be folded (imagingaxis a₁ of module 10-19 of FIG. 4n is folded and has differentdirections at the light entry le and light receive 1 r positions ofmodule 10-19). FIGS. 6n, 6 o, and 6 p show alternative types of aimingpattern generating systems that may be incorporated in an imaging modulein which light generated by an aiming LED such as LED 18 is folded. Inthe embodiment of FIG. 6n aperture 43 which may be imaged by lens 25onto a target T is positioned forward of light reflective element 640 inthe optical path. This embodiment is useful where light pipes are usedin combination with aiming LEDs to prevent divergence of the aimingillumination light rays. In the embodiment of FIG. 6o aperture 43 whichmay be imaged by lens 25 onto a target T is positioned forward of LED 18and optically rearward of light reflective element 640 in the opticalpath. The embodiment of FIG. 6p includes an aperture 43 positionedbetween light source 18 and light reflective element 43 r and an opticalelement 25 p including a prism for imaging light from aperture 43 onto atarget and for redirecting aiming illumination light reflected fromreflecting element 643. Optical element 25 p includes a prism defined ona light entry surface therof and an imaging lens surface (spherical orcylindrical) on a light exit surface. It is seen that the embodiment ofFIG. 6p including a light redirecting prism 25 p, can be utilized forreducing the height requirements of an imaging device in which thesystem is installed. Folded optic aperture aiming systems are readilyincorporated into aiming optical light pipes as shown by FIG. 6q. InFIG. 6q, light pipe 311 transmits light from aiming light source.Incorporated into light pipe 311 is an aperture stop 641 defining anaperture 43. Disposed at distal end 314 of light pipe 311 is an aimingoptic 25 for imaging aperture 43 into target space.

[0156] Referring to other aiming patterns which may be projected bymodules of the invention, a split line aiming pattern is shown in FIGS.6i and 6 j. The split horizontal line aiming pattern shown in FIG. 6imay be formed by providing, as shown in FIG. 6s, aiming pattern wedges29 on the light entry surface of optical plate 26 opposite aimingpattern cylindrical lenses 25. Aiming pattern wedges 29 operate todirect light from aperture slits 43 outwardly toward the sides of atarget area T so that a gap 650 between two horizontal line segments 648is defined in the center of a module's field of view when the module iswithin a range of distances from a target at which it can capture imagedata of acceptable quality at (the best focus distance of the module iswithin this range). The split line aiming pattern comprising segments648 allows a user to easily align the center of the module's field ofview with a center of a region of interest.

[0157] It may be desirable to restrict the width of a split horizontalline aiming pattern 647 comprising segments 648 so that line segments648 do not extend substantially beyond a reader's target area T asdefined by a reader's field of view. In order to restrict the width ofsplit horizontal line aiming pattern comprising segments 648, verticallyoriented cylindrical lenses may be superimposed on aiming pattern wedges29 as is illustrated in FIG. 2j to form combined wedge and verticallyoriented cylindrical lens elements 29′. Aligning combined wedge and lenselements 29′ with slit aperture 43 provides an aiming pattern having thefeatures shown in FIG. 6j, wherein split horizontal line aiming patterncomprising segments 648 is contained substantially within a target areaT defined by a reader's field of view.

[0158] When positioned relative to apertures 43 as shown in theparticular embodiment of module 10-9, cylindrical lenses 25 of opticalplate 26 operate to converge and thereby image light from aperture slits43. In the modules described shown having aiming optics 25 sharpness ofaiming pattern 630 preferably will not vary substantially as thedistance of module 10 to a target is varied. Optics 25 may be adapted toconverge (and thereafter diverge) light gradually. Because optics 25 canbe adapted to gradually converge light rays optics 25 could be describedas providing the function of substantially collimating light. Further,optics 25 can actually collimate or even diverge light rays exitingoptics 25 provided an aiming system includes features resulting in asharp aiming pattern being projected on target, T. Optics 25 may includemultiple features which result in pattern e.g. 630 appearing sharp overvarious module-to-target distances.

[0159] In one variation of the invention, aiming illumination optics areprovided so that the sharpness of aiming lines e.g. lines 648 variesdepending on the module to target distance. More specifically, aimingillumination optics may be provided so that aiming lines e.g. 648 aresubstantially most sharp at the best focus position of module 10 andless sharp when a reader equipped with module 10 is moved away from thebest focus position.

[0160] Referring to further aspects of the invention it will beunderstood that in any of the modules described herein, aiming lightsources 18 could be provided by laser diode assemblies. When aiminglight sources 18 are provided by laser diode assemblies of the typeincorporating a built-in collimating lens it may be consideredunnecessary to include elements such as aperture 43, or optics 25 sincesuch laser diode assemblies inherently produce a crisp aiming patternover a wide range of module (reader) to target distances. An aimingpattern generated by a laser diode assembly aiming light source 18 maybe a spot of light in target area, T. Module 10-21 of FIG. 6k includesillumination light sources 16 provided by surface integrated LEDs andaiming light sources 18 provided by laser diode assemblies. Imagingmodule 10-21 may project an aiming pattern as shown by FIG. 6L. Laserdiode assembly aimers 18 may project two dots 637, 638 onto target, T.If diode assemblies 18 are canted, imaging module 10-21 can be adaptedso that dots 637, 638 converge at a best focus distance.

[0161] In another useful embodiment of the invention, emit opticscomprising optical element 25 aperture 43 and light source 18 arecoordinated with receive optics 40 so that a best focus emit opticalmodule-to-target distance (at which an optimally focused image ofaperture 43 is projected on a target) is greater than a receive opticmodule-to-target distance (at which an optimally focused image of atarget indicia, e.g. a bar code is incident on image sensor 32). Such anembodiment is highly useful in a 1D embodiment as shown by module 10-22,wherein an aiming pattern may serve as an illumination pattern.Configuring module 10-22 to have an emit optical best focus distancegreater that a receive optical best focus distance has been observed toimprove a depth of field of module 10-22. At reader distances about thebest receive optic focus distance, module 10-22 because of high imagequality can be successfully employed to read bar codes with a less thanoptimally focused aiming and pattern being imaged onto a target, T. Atlonger distances that are about the distance of the best emit-opticalfocus distance the optimally focused illumination pattern yields a highsignal to noise ratio, and module 10-22 can successfully decode indicaat the longer distance. In one example of module 10-22, module 10-22 isestablished to have a best emit optical focus distance (at whichaperture 43 is optimally focused on a target) of greater than about 7inches and best focus receive optical focus distance (at which anindicia is optimally focused onto sensor 32) of less than about 5inches.

[0162] In the embodiment of FIG. 6u optical plate 26 includes imagingoptics 29′ on a light entry surface thereof for restricting a width ofaiming pattern line segment 648. It may also be desirable to includediffusers 27 on plate 26 in the optical path of light emitted by aiminglight sources 18 for the purpose of homogenizing aiming light. It may bedesirable, for example, to homogenize light emitted from aiming lightsources 18 in a horizontal plane. FIGS. 6v, 6 w, and 6 x show cutawaytop views of various optical plates 26 taken along a row of aiming lightsources 18. Optical plates 26 shown in FIGS. 6v, 6 w, and 6 x mayrepresent optical plates of e.g. module 10-1, module 10-9, or module10-22. In the example of FIG. 6v optical plate 26 includes diffractiveoptic diffusers 27 a for homogenizing aimer pattern light in ahorizontal plane. In the example of FIG. 6w, optical plate 26 includesrefractive optic vertically oriented cylindrical microlens diffusers 27b for homogenizing aiming light in a horizontal plane. In the example ofFIG. 6x, optical plate includes vertically oriented cylindrical negativelenses 27 c for homogenizing light in a horizontal plane.

[0163] While aiming optics 25 have been described herein as beingpositioned on a light exit surface of optical plate 26 and aimingdiffusers 27 have been described as being formed on light entry surfacesof optical plate 26, aiming optics 25 could be formed on a light entrysurface and any one of aiming diffusers 27 a, 27 b, and 27 c could beformed on a light exit surface of optical plate 26. Furthermore, morethan one aiming system optical element could be formed on a singlesurface. A vertically oriented cylindrical microlens diffuser 27 b couldbe integrated into a cylindrical lens 25 c of a plate light exit surfacefor example.

[0164] A description of how, in one embodiment, an aiming patterngeneration system comprising an aiming light source 18, an aperture 43,and optics 25 (e.g. a cylindrical or spherical lens) can generate asharp, crisp aiming line at a wide range of module-to-target distances(reader-to-target distances when module 10 is integrated in a reader) isprovided with reference to FIG. 6y. In the imaging module side view ofFIG. 6y, imaging lens 25 having focal point 668 projects an optimallyfocused image of aperture 43 at image plane 669. Light rays 670, 671,672, and 673 are light rays drawn to indicate the location of imageplane 669 and the size of the aperture image at image plane 669. Lightrays 674, 675, 676, and 677 are limit rays for the system of FIG. 6y, asare defined by an aperture stop function provided by lens 25. It is seenthat at reading distance 678, an optimally focused image of aperture 43,and therefore a crisp, sharp aiming pattern e.g. aiming pattern 630 isprojected on target T. At near reading distances e.g. distance 679, aless than optimally focused image of aperture 43 is imaged onto targetT. Nevertheless, the projected image is crisply and sharply definedbecause substantially no light emanating from aperture 43 can reachlocations beyond the boundaries delimited by limit rays 674 and 675. Atfar reading distances e.g. distance 680 a less than optimally focusedimage of aperture 43 is also imaged onto target T. Nevertheless, the farfield projected image of aperture 43 is sharply and crisply definedsince substantially no light emanating from aperture 43 can reachpositions outside of the boundary defined by limit rays 676 and 677. Itcan be seen from observation that a height dimension of aiming patterne.g. 630 can be controlled by controlling the height dimension of lens25. A thinner aiming line can be produced by decreasing the heightdimension of lens 25. Further, the crispness and sharpness of an aimingpattern e.g. aiming pattern 630 can be improved by providing a sharplydefined opaque aperture stop member or members about the borders of lens25. Opaque aperture stop members 681 as shown in FIG. 2n (module 10-9)and in FIG. 6m (module 10-22) and FIG. 1m (module 10-1) can be providedby a sharp edged mechanical member attached, adhered or otherwiseaffixed to lens 25 or else may comprise a material which is sprayed on,painted on, or other deposited on a surface of lens 25.

[0165] Another aiming system which results in a crisp, sharply definedaiming pattern being projected over a wide range of module-to-targetdistances is described with reference to Example 1. In Example 1, anaperture aiming system is provided having a very small aperture heightof less than 1.0 mm. A size of aperture 43 can readily be reduced in a2D imaging module embodiment having separate illumination light sourceswithout compromising image capturing performance in that aimingillumination does not need to be utilized in the generation of imagedata as it is in many 1D imaging modules. The aiming system described inExample 1 is well suited for incorporation into e.g. module 10-1 shownin FIG. 1a.

EXAMPLE 1

[0166] An aiming pattern generation system 685 comprising a pair ofaiming LEDs 18, a pair of apertures 43, and a pair of spherical lens 25s substantially as shown in FIG. 1h is designed such that each half ofthe aiming pattern generating system has the properties as presented inTable 1. TABLE 1 Aperture size: 1.85 mm (W) × 0.3 mm (H) LED (18):Agilent Subminiature HLMP QM00 (690mcd) PCB (14a) to aperture (entry1.07 mm surface) distance: Aperture to lens member light 4.1 mm entrysurface distance: Lens thickness: 1.7 mm Back focal length: 5.16 mmFront focal length: 5.16 mm Lens (25s) radius of r2 = −3 mm curvature:Lens material: Polycarbonate Paraxial magnification: −1.028

[0167] Aiming system 685 generates aiming pattern light rayssubstantially as is illustrated in the computer modeled side view ofsystem 685 of FIG. 6z. It is seen that the small size of aperture 43substantially prevents light rays from reaching borders 686 of lens 25 sin the vertical plane (aiming light rays may reach borders 686 in thehorizontal plane, thus the lens aperture effect described with referenceto FIG. 6y may apply in the horizontal plane). Instead the bundle oflight rays emanating from aperture 43 are substantially concentrated sothat they are incident on the lens member including lens surface 25 stoward a center (axis) of the lens member in the vertical plane.Although an imaging plane for the system described (at which an image ofthe aperture is optimally focused onto a target T) was determinedempirically to be defined substantially on the order of millimeters fromlens 25 s, an aiming pattern imaged onto a target T far distancessubstantially away from the distance of optimal focus (such as beyond 7inches) was nevertheless observed to be sharp and crisp andsubstantially narrow although substantially thicker than at shorterreading distances. Light rays exiting lens 25 s were observed togradually diverge in the vertical plane (on the order of about 2degrees) at distances beyond empirically estimated image plane 688.Accordingly, because of the gradual divergence of light rays exitinglens 25 s, a height dimension (thickness) of the pattern imaged onto atarget remained substantially narrow and within the field of view ofimage sensor 32 at longer module-to-target distances away from thedistance of optimal focus, and was observed to be crisply defined,corresponding to the shape of aperture 43 at longer distances (over 7in.). The gradual divergence of light rays was believed to be the resultof light entry light rays being substantially concentrated toward acenter (axis) of the lens member including lens 25, and possibly,diffractive optic properties attributable to the small height dimensionof aperture 43.

[0168] In Table 2, characteristics of an aiming pattern generated bysystem 685 at various module to target distances are summarized. TABLE 2Height Width Module to Height Width angle angle Target Distance (mm)(mm) (deg.) (deg.) Field of View 2″ (50.8 mm)  3 mm  30 mm 1.69 16.4 37mm × 28 mm 4″ (101.6 mm) 6 mm  44 mm 1.69 12.2 64 mm × 48 mm 6″ (152.4mm) 9.5 mm 59 mm 1.79 10.9 95 mm × 71 mm 8″ (203.2 mm) 13 mm  72 mm 1.8310.0 120 mm × 90 mm 

[0169] The projected aiming pattern at various distances characterizedin table 2 are illustrated as shown in FIGS. 7a-7 d. The shape of theaiming pattern was observed to be a sharply defined rectangle. Theprojected aiming pattern, at the various distances exhibited a sharpnesssubstantially as depicted in FIGS. 7a through 7 d. Importantly, aimingpattern 631 projected by system 685 exhibits sharply defined lateraledges 632. Further, sharply defined lateral edges 632 of pattern 631 arealways, in the system described at the distances considered projectedwithin a field of view of image sensor 32 as delimited by T and aspresented in Table 2. Aiming pattern 631 is preferably projected so thatsharply projected edges 632 are projected just within (as shown), on, orjust outside of a field of view of image sensor corresponding to atarget area, T. Configuring system 685 to project an aiming pattern 631having sharp lateral edges 632 proximate a lateral boundary of a fieldof view results in an aiming pattern that is useful in aiding thelateral centering of a field of view of module 10 on a target indicia.The selection of spherical lens 25 s which operates to image light raysin both a horizontal and vertical planes, results in sharp lateral edges632 of aiming pattern 631 being defined. Aiming system 685 may be usedin combination with a receive optical system having a best receive focusdistance of about 7 inches incorporated in an imaging module configuredin read common types of decodable dataforms in a reading range of fromless than about 1 inch to greater than about 15 inches.

[0170] D. Illumination Device Architectures

[0171] Referring again to module 10-2 shown in FIG. 2a module 10-2includes surface integrated illumination LEDs 16 and surface integratedtarget LEDs 18. Surface integrated LEDs are LEDs of a type having a dieplaced directly on a printed circuit board. In the embodiment of module10-2 printed circuit board 14 b carries four illumination LEDs 16 and apair of aiming LEDs 18. Referring to FIGS. 8a-8 b illumination LED dies16 d working in combination with illumination optics 16 p flood a targetarea with substantially uniform illumination. Target LED dies 18 dtogether with targeting optics, 43 and 18 p project an aiming patterninto a target area, T. As explained in copending application Ser. No.09/802,579 filed Mar. 8, 2001 entitled “Imaging Module for OpticalReader Comprising Refractive Diffuser” incorporated by reference, theaiming pattern projected by target LEDs and their associated optics maycomprise, for example, a straight line, a split line, or a geometricshape.

[0172] Further details of surface integrated LEDs are described withreference to cross sectional diagram of FIG. 8a and the exploded topview of FIG. 8b. Referring to the cross sectional view of FIG. 8asurface integrated LEDs 16 and 18 are integrated in a printed circuitboard assembly comprising a printed circuit board substrate 14 s, anepoxy layer 14 e, and lenses 16 p and 18 p disposed over epoxy layer 14e in opposing relation relative to LED dies 16 d and 18 d, respectively.It is known that an epoxy layer 14 e of a surface integrated LED issemitransparent. Surface integrated LED circuit board 14 s is secondcircuit board 14 b of module 10-2 and first circuit board 14 a of module10-3. Dies 16 d and 18 d have associated therewith wire bonds 16 w and18 w which allow electrical current to be circulated through dies 16 dand 18 d. Accordingly, in the embodiment shown, illumination LEDs 16have a single or multiple LED die 16 d per LED and aiming LEDs 18include a single LED die 18 d per LED. LED dies 16 d, 18 d are disposedin reflector cups 14 r formed in surface of PCB substrate 14 s.Reflector cups 14 r may be manufactured by machining away the cupsection 14 r from PCB 14 a. Surface 14 c of each reflector cup 14 r iscoated with a reflective material such as gold, silver, aluminum, etc.

[0173] After LED dies are deposited in reflector cups 14 r, an epoxylayer 14 e is layered over PCB substrate 14 s. Lenses 16 p and 18 p aresimultaneously formed over epoxy layer 14 e in opposing relationrelative to cups 14 r. In the embodiment shown, illumination LED lens 16p preferably includes diverging optics (and therefore is also labeledelement 27) for diverging light rays from illumination LED dies 16 dinto a target space in a substantially uniform pattern. Lens 18 ppreferably includes converging optics for converging light rays fromlight emanating from LED die 18 d and therefore is also labeled element25. The edges 16 e and 18 e of lenses 16 p and 18 p are shown in FIG.1f. In one embodiment a slit aperture as indicated by dashed line 43,may be disposed in association with LED die 18 d and lens 18 p so thatlens 18 p images aperture 43 onto a target defined by a field of view ofimage sensor 32. Slit aperture 43 may be embedded in epoxy layer 14 e asindicated by dashed-in aperture slit 43 of FIG. 1e or else slit aperture43 may be formed above or below epoxy layer 14 e. Reflector cups 14 rmay have index matching epoxy disposed therein. The epoxy may also havetitanium oxide added thereto as a dispersal material to aid diffusion.

[0174] In module 10-1, as best seen in FIG. 1h, aimer LEDs 18 andillumination LEDs 16 are provided by side-leaded surface mounted backbenched LEDs as are illustrated by the exploded side view as shown inFIG. 7e. Side-leaded surface-mounted LEDs, like traditional leaded LEDshave leads 18L extending therefrom but unlike traditional leaded LEDsthe leads 18L extend from the sides of LED 16, 18. The side extendingleads 18L are sometimes referred to as “gull wings.” Side leaded surfacemounted LEDs further have substantially planar back surfaces 18 pb asdepicted in FIG. 7e. Back surface 18 pb can be manufactured to besubstantially planar since back surface 18 b is devoid ofbottom-extending leads as in a traditional leaded LED. Planar, leadlessback surface 18 pb allows LEDs 18 to be readily back benched against PCB14 b or another planar member, thereby allowing LEDs 18 to be readilyinstalled at a precise orientation (in module 10-1, a normal angleorientation). Further, the mounting of side-leaded LEDs isuncomplicated, since there is no need, as in a traditional leaded LED tosolder the LED on a side of a printed circuit board opposite the side onwhich it is benched. Importantly, side leads 18L of a side-leadedsurface mount LED, unlike solder tabs of traditional surface mount LEDscan readily be soldered to a printed circuit board without altering aprecise right angle orientation of the LED as is controlled by the backbenching of the LED on circuit board. As shown in FIG. 1h, side leadedillumination LEDs 16 mounted so that LEDs 18L are at angles relative toan X and Y axis. Mounting LEDs 16 at angles provides substantial spacingbetween LEDs 16L and post 84, which is typically conductive.

[0175] It will be appreciated that a precise angular orientation of LEDsrelative to the Z axis shown in FIG. 1h is highly important in manyembodiments described herein. Precise angular orientation of LED 16,18relative to the Z axis is achieved by back benching of a side-leadedsurface mount LED against circuit board 14 a, 14 b. Tight back mountingof LEDs also reduced a Z direction space consumed by LEDs 16, 18.Further, use of side-leaded surface mount LEDs eliminates the need forextraneous alignment members or extraneous LED alignment steps in theassembly process.

[0176] One example of a side leaded surface mount LED which may beutilized with the invention is the HLMX “Subminiature High PerformanceAlInGaP” series LED manufactured by Agilent Technologies, Inc. of PaloAlto, Calif. Flat top HLMX-PXXX Agilent lamps have wide radiationpatterns and therefore are more useful, in certain applications whenemployed as illumination LEDs 16. Domed HLMX-QXXX Agilent lamps havemore narrow radiation patterns and therefore, in certain applicationsare more useful when employed as aiming LEDs 18. In certainapplications, both aiming and illumination LEDs 16,18 are provided bydomed HLMX QXXX lamps.

[0177] Variations of molded light pipe and LED assemblies described withreference to FIGS. 4a-4 n are now described in greater detail withreference to FIGS. 8c, 8 d, and 8 e. In the embodiment of FIG. 8c lightpipe and light source assembly 370 includes a single surface mount LEDpackage 92-1 mounted to PCB 14 (e.g. 14 a, 14 b). LED 92-1 includes asingle LED die. Further with reference to the embodiment of FIG. 8clight pipe 311 is manufactured and mounted so that primary lightrefractive surface 376 of light pipe 311 forms a constant substantially45 degree angle with PCB 14.

[0178] In the embodiment of FIG. 8d light pipe and light source assembly371 includes a multiple lead frame surface mount package 92-2. LED 92-2has three LED dies LD mounted therein and a single Bragg reflector R.Disposing multiple LED dies LD in a LED package having a single Braggreflector R reduces the size of the surface mount LED package. Furtherwith reference to the embodiment of FIG. 8d the light entry surface oflight pipe 311 are separated into three sections se₁, se₂, and se₃, eachcorresponding to one of the LED dies LD. Each light entry surface se₁,se₂, and se₃ forms a different angle with PCB 14 so as to optimize theefficiency of light transmission through light pipe for each of the LEDdies LD. A diffuser 27 can be molded onto distal end of light pipe 311.Diffuser 27 diffuses light from light pipe 311 and further reducesfresnel losses.

[0179] In the embodiment of FIG. 8e light pipe and light source assembly372 includes a LED having three LED dies LD, each formed by mounting alight emitting die on PCB 14 directly, and disposing epoxy e over theassembly of PCB mounted dies. Direct mounting of LED dies LD onto PCB 14reduces the size of LED package 92-3. Further, referring to theembodiment of FIG. 8e the primary light reflective surface sr ofassembly 372 is divided into three sections sr₁, sr₂, and sr₃ eachcorresponding to a different one of the LED dies LD. Each section sr₁,sr₂, and sr₃ of light reflective curved surface sr forms a differentangle with PCB 14 so as to optimize the efficiency of light transmissionthrough light pipe 86-2 for each of the LED dies LD. For reducingFresnel losses in system 372, the index of refraction, N_(e), of epoxy ecan be selected to substantially match the index of refraction, N_(p),of molded light pipe 311.

[0180] Assembly 372 of FIG. 8e and assembly 371 of FIG. 8d illustratetwo different systems for optimizing the efficiency in lighttransmission through a light pipe in a light pipe and source assemblyhaving multiple dies. LEDs 92-2 and LED 92-3 are single light sourceswhich comprise multiple dies. It will be understood that either of thesesystems can be employed in a light pipe and light source assembly havingmultiple light sources, wherein the multiple sources comprise standardsurface mount LEDs having one Bragg reflector per die or standard singledie leaded LEDs. Light rays LR depicted in FIGS. 8c, 8 d, and 8 e areshown as originating from ideal light sources LD. It is understood thatactual light sources exhibit substantially greater variety in the originand angles of the incident rays. It will be understood further that anyof the LEDs, e.g. LED 16, LED 18 described herein can be provided by anLED package having multiple LED dies incorporated therein. InfineonCorp. of Munchen, Germany specializes in designing and manufacturingLEDs comprising multiple LED dies.

[0181] Apparatuses for increasing the efficiency of LEDs 16 and 18 aredescribed with reference to FIGS. 8f and 8 g. In the system describedwith reference to FIG. 8f, purchased part surface-mount LED 18, 18 s ismounted to PCB 14 (e.g. PCB 14 a, 14 b) and clear epoxy lens 18L ismolded over surface mount LED 18, 18 s. The lensing provided by lens 18Lreduces the amount of divergence of light emanating from the LED. In thesystem described with reference to FIG. 8g, leaded LED 18 is mounted toPCB 14 (e.g. 14 a, 14 b) and a substantially box-shaped lens cap 18 c ismounted over LED 18. Lens cap 18C, like lens 18L reduces the amount ofwhich light emanating from LED 18 diverges. Reducing the divergence oflight rays emanating from an LED is particularly useful in the casewhere LEDS are aiming LEDs configured to be directed toward an aperture.However, some designers may place a premium on “filling” a completeaperture. The system comprising LED 18 s and lens 18L may be consideredgenerically as an LED 18. Likewise the system comprising LED 18 and lens18L in FIG. 7m can be considered generically an LED 18.

[0182] E. Illumination/Aiming Color Emission Control and Coordination

[0183] It is seen that illumination light source 16 in the embodiment ofFIG. 8b includes a plurality of LED dies 16 d. As shown in FIG. 8hillumination light source 16 of module 10-23 which may be incorporatedin any one of reader housings 111 to define a reader 110 may be amultiple color emitting light source having multiple LED dies 16 d, eachbeing independently driveable, and each having an emission wavelengthband different from the remaining LED dies. Illumination light source16, 16MC shown in FIGS. 8h and 1 z is a multiple color emitting lightsource having three LED dies 16 d-1, 16 d-2, and 16 d-3. Multiple colorLEDs 16 mc, 18 mc can be incorporated in any of the modules 10-1 to10-22 described herein. First LED die 16 d-1 is independently driveableto emit light in the blue light wavelength band; second LED die 16 d-2is independently driveable to emit light in the green light wavelengthband and LED die 16 d-3 is independently driveable to emit light theamber wavelength band. The set of signals presented by control circuit140 to LED 16MC may be termed a set of LED die driver signals. Controlcircuit 140 can be controlled to alter the current flow to LED 16MCbased on the present application of the reader 110. Multiple coloremitting light sources 16 and 16MC can be, for example, a model LATBcolor light source of the type available from Infineon TechnologiesCorporation of San Jose, Calif., USA.

[0184] Different surfaces often respond differently to different typesof illumination depending on their shape, color, and type of material.Control circuit 140 can be configured so that if decoding of a bar codefails using a first set of LED die driver signals, control circuit 140automatically presents a second set of LED die driver signals to LEDs 16and 16MC, and a third set of LED die driver signals to LEDs 16 and 16MCif a decoding fails a second time, and so on until decoding issuccessful. Control circuit 140 can be configured so that controlcircuit 140 saves the set of LED driver signals yielding a successfuldecode, and applies that set of driver signals to LED 16 and 16MC thenext time trigger 13 t is pulled to actuate decoding.

[0185] In another embodiment of the invention, reader 110 is configuredso that the set of LED die driver signals presented by control circuit140 to LEDs 16 mc is selectable by an operator so that the color emittedby LED dies 16 d-1, 16 d-2, and 16 d-3 in combination is optimized forthe application in which reader is presently being employed. Forexample, if reader 110 is to be used to decode bar codes formed on acertain metallic surface, an operator may configure reader 110 so thatcontrol circuit 140 presents to LED 16MC a set of LED driver signalsthat have previously been determined to be well-suited for use incapturing images formed the certain on metallic surfaces. An operatormay also wish to change the color emitted by LEDs depending on thecolors present in a target area comprising an indicia. For example, if atarget area comprises red indicia formed on a white background, anoperator may configure control circuit 140 e.g. via selection of a menuoption so that control circuit 140 presents a set of LED die driversignals operative to result in LEDs emitting white light, which willoptimize contrast in a captured frame of image data in the casecomprises red indicia formed on white substrate.

[0186] Reader 110 can be configured so that selection of a particularone or more control buttons of keyboard 13 k in response to display ofcertain indicia of display 14 d results in a certain set of LED diedriver signals being presented by control circuit 140 to multiple coloremitting LED 16 and 16MC. Reader 110 can also be configured so thatreading of a certain type of “menu symbol” as will be described ingreater detail herein results in a certain set of LED die driver signalsbeing presented to multiple color emitting LED 16.

[0187] Reader 110 can also be configured so that the set of LED driversignals presented to LED 16MC changes automatically in response to asensed condition sensed by reader 110, such as a sensed conditionrelating to ambient light, the colors of indicia present in a target,the material conditions of a target, the reader-to-target distance, thelevel of focus of an image, the shape or surface characteristic of atarget, for example. Reader 110 can automatically sense ambient lightconditions by analysis of a captured frame of image data without anyreader driven illumination. Reader 110 can determine reflectivityconditions of a target by analysis of a captured frame of image datacaptured under known illumination conditions. Various automatic rangedetermination and focus level detection methods are known by skilledartisans. As is well known, the reader-to-target distance of a readercan be detected by angularly directing a spot of light at a target froma reader housing and estimating the reader-to-target distance based onthe position of the spot in a captured image. The degree of focus of animage can be detected by several methods including the method describedin commonly assigned U.S. Pat. No. 5,773,810, issued Jun. 30, 1998incorporated herein by reference. Reader 110 can be configured so thatthe color emitted by illumination LEDs 16MC and/or aiming LEDs 18MCchanges depending the reader-to-target distance or degree of focus of animage. For example, control circuit 140 may control LEDS 16MC to (and/or18MC) automatically emit red light (indicating “TOO HOT” condition) ifthe reader-to-target distance is less than a desired minimumreader-to-target distance control circuit 140 may control LEDs 16MC(and/or 18MC) to automatically emit white light if the reader-to-targetdistance is within a range of acceptable distances, and may control LEDs16MC (and/or 18MC) to automatically emit blue light (indicating a “TOOCOLD” condition) if the reader-to-target distance is greater than adesired maximum reader-to-target distance. Similarly control circuit 140may control LEDs 16MC (and/or 18MC) to automatically emit, e.g. bluelight if the most recent captured image is exhibiting an unacceptabledegree of focus, and to control LEDs 16MC (and/or 18MC) to automaticallyemit, e.g. white light if a most recently captured image exhibits anacceptable degree of focus.

[0188] The presence or absence of a certain color present in a targetarea can readily be detected for by employing in reader 10 a color imagesensor, activating an appropriate color filter correlated with the colorbeing detected for, and analyzing image signals generated by the colorimage sensor. Advantages and benefits of utilization of a color imagesensor in reader 110 are discussed more fully in application Ser. No.09/904,697 entitled “An Optical Reader Having a Color Imager” filed Jul.13, 2001, incorporated herein in its entirety by reference.

[0189] The variable emission color features described herein can beyielded by providing different colored monochrome light sources ratherthan multicolor light sources. For example an illumination system cancomprise a bank of monochrome red LEDs and a bank of monochrome blueLEDs. Control circuit 140 can change to color of illumination of anillumination target from red to blue by deactivating the bank of redLEDs and activating the bank of monochrome blue LEDs.

[0190] Multiple color emitting LED dies also can be utilized as aimingillumination LEDs as is indicated by aiming LEDs 18MC shown in FIG. 1r.Control circuit 140 can present different to multicolor aimer LEDillumination source 18MC different sets of LED driver signals dependingon the mode of operation of reader 110. For example, if reader 110 isoperating in a decoding attempt mode, control circuit 140 may present tomulticolor aimer LED 18MC a set of LED driver signals which result ingreen light being radiated from aimer LED 18MC. If reader 110successfully decodes a bar code, control circuit 140 may present a setof LED driver signals to multicolor LED 18MC which result in multicoloraimer LED 18MC radiating red light. That is, control circuit 140 maygenerate a good read indicator by causing the color of illuminationradiating from aimer illumination LEDs 18MC to change from a first colorto a second color when there has been a successful decode of a bar codeor character control circuit 140 can also indicate a successful read, oranother change in operating state by changing the set of LED driversignals that are presented to illumination LEDs 16MC when a bar code orcharacter has been successfully decoded.

[0191] The contrast between aiming illumination pattern 630 andbackground illumination pattern 520 can be enhanced by selecting aiminglight sources 18 so that aiming light sources radiate light of a colordifferent than illumination light sources 16.

[0192] In one embodiment of the invention, illumination LEDs 16 of e.g.module 10-1 comprise red light LEDs and aiming LEDs comprise green lightLEDs or blue light LEDs. Selecting aiming LEDs to project light of acolor different than illumination LEDs results in an aiming pattern 74being projected onto a target T in a color different than that ofbackground pattern 74 which enhances an operator's ability to perceivean aiming pattern relative to an illumination pattern. If aiming lightsources 18 and illumination sources 16 are selected to emit light atdifferent colors the received light reflected from target can befiltered so that light from only one of the different colors is receivedby image sensor. FIG. 6m shows a color filter 450 incorporated in a 1Dimage module 10-22. FIG. 3g shows a color filter 450 incorporated in 2Dimaging module 10-11. Color filter may be a bend pass filter whichpasses light of a wanted color or a blocking filter which blocks lightof an unwanted color. With filter 450 in one application light fromaiming light sources 18 can be filtered (if different in color emissionthan illumination sources 16, so that it is not necessary to “flicker”aiming light sources 18 of backout pattern 630 electronically.

[0193] The particular combination of colors forming an aiming patternand illumination pattern can be selected based on the expectedparticular application of the optical reader in which the illuminationand aiming illumination light sources are to be incorporated. Instandard bar code reading application in which it is expected that thereader will encounter black-on-white printed indicia, illumination LEDs18 can be selected to emit red light and aiming illumination LEDs can beselected to emit blue light, for example, to form the contrastingillumination patterns indicated in FIG. 85. In an application where anoptical reader is expected to read fluorescent orange postnet codes,illumination LEDs 16 can be selected to emit green or blue light andaiming LEDs 18 can be selected to emit red light. In an applicationwherein an optical reader 10 is expected to be used to read red-on-whiteprinted indicia, illumination LEDs 16 can be selected to emit whitelight and aiming LEDs 18 can be selected to emit red, green, blue, oryellow light. In an application wherein optical reader 10 will be usedin a photo processing darkroom, illumination LEDs 16 can be selected toemit light in the infrared spectrum and aiming LEDs 18 can be selectedto emit red, green, blue, or yellow light.

[0194] Table 3 below summarizes the above described illumination lightsource-aiming light source and application correlations is presentedhereinbelow. TABLE 3 Illumination Color Aimer Color PossibleApplications Red Green or Blue Standard bar code reading. Green or BlueRed Different color light provides better contrast on certain bar codetypes such as fluorescent orange postnet codes. White Red, green, blue,Standard bar code reading, or yellow imaging of red indicia. IR Red,green, blue, Secure bar code applications, or yellow photo processingdarkroom applications. UV Red, green, blue, Secure bar codeapplications. or yellow

[0195] Utilization of white illumination LEDs provides numerousadvantages. White light is less distracting than is red light. Red lightillumination patterns have been observed to cause eye strain andheadaches. Furthermore, the color red indicates danger in many types ofindustrial applications. Thus, the use of white light avoids the problemof red illumination light being erroneously interpreted to indicate adanger condition by persons working in proximity with reader 10. Stillfurther, use of white light illumination light sources allowsred-printed indicia such as red ink signatures, red bar codes, and red“chops” as used in Asia to be imaged. Further, use of white lightillumination light sources provides good contrast between anillumination pattern and an aiming pattern when aiming illumination LEDsare selected to emit light in a narrow (non-white) band.

[0196] By utilizing multiple color emitting light source LEDs 16MCand/or aiming LEDs 18MC, different combinations of contrastingillumination and aiming patterns can be realized simply by presentingdifferent sets of LED die driver signals to aimer LEDs 18MC andillumination LEDs 16MC without physically removing and replacing theLEDS and without increasing the size of module 10 as would be necessaryif different LEDs were added to module 10. Reader 110 having multiplecolor emitting light source illumination and aiming LEDs 16MC and 18MCcan be configured so that a user can actuate control inputs to changethe particular color combination defined by background pattern 72 andaimer pattern 74. The color contrast combination between an illuminationpattern and aiming pattern can also be made changeable by providing inreader 110, separate banks of different-colored monochrome illuminationlight sources and/or aiming illumination light sources which may beselectively activated depending upon the operating mode of reader 110.However, such a solution would significantly add to the size of module10.

[0197] As indicated by reader 110 of FIG. 8k control circuit 140 can beprogrammed to display on display 14 d a set of user selectableapplication settings, which are selectable by one of a well know menudriver selection methods as are explained in commonly assigned U.S. Ser.No. 09/858,163 entitled “Multimode Image Capturing and Decoding OpticalReader” filed May 15, 2001, incorporated herein by reference. In theembodiment shown in FIG. 8k display 114 d displays to a user variousapplication settings, namely “standard bar code,” “orange postnet code,”“red indicia,” and “secure bar code.” When one of the application menuoptics is selected, control circuit 140 presents a set of LED die driversignals to LEDs 16MC and 18MC corresponding to the menu selection inaccordance with the application-pattern correlations listed on Table 1.That is, if the standard bar code option is selected, control circuit140 may present a set of LED die driver signals to LEDs 16MC and 18MCsuch that illumination LEDs 16MC emit red light and aimer LEDs emit blueor green light. If the “red indicia” option 14 d-r is selected, controlcircuit 140 may present a set of LED die driver signals to LEDs 16MC and18MC such that illumination LEDs emit white light and imager LEDs emitred light, and so on.

[0198] Reader 110 can also be configured so that the particularcombination of colors projected by aiming LEDs 18MC and illuminationLEDs 16MC changes automatically in response to a sensed condition.

[0199] For example, reader 110 can be configured so that if reader 110senses the presence of red indicia in a target area in a mannerdescribed previously, control circuit 40 can present a set of LED driversignals to LEDs 16MC and 18MC such that illumination LEDs 16MC emitwhite light and aiming LEDs 18 c emit blue light, an illuminationpattern color combination that is well-suited for imaging a target andcomprising red indicia.

[0200] F. Receive Optics

[0201] When the size of module 10 is reduced, the sensitivity of module10 to changes in the distance of lens assembly 40 to image sensor 32. Itis therefore advantageous to provide an arrangement between lensassembly 40, shown as a lens barrel 40 and lens retainer 82 that allowsbarrel 40 to be finely adjusted within retainer 82. An imaging lensincorporated in a lens assembly 40 may be, for example, a single elementlens, a two element lens (a lens doublet), a three element lens (a lenstriplet), a lens or lenses of assembly 40 may be made of variousmaterials, e.g. glass, plastic.

[0202] In the prior art, lens barrels commonly comprised threads 40 t ontheir outer surface which are received in threads 82 t of retainer 82 asshown in FIG. 11. The lens-to-image sensor distance in a threaded lensbarrel system is adjusted simply by threading barrel lens assembly 40into retainer 82 until a desired lens-to-image sensor distance isachieved.

[0203] The precision with which the distance of a threaded lens barrelcan be adjusted can be increased by changing the thread count of thebarrel 40 and the retainer 82. However, the cost of manufacturing barrellens assembly 40 and retainer 82 increases substantially as the threadcount of the system increases.

[0204] A low cost and finely adjustable barrel and lens holder system isdescribed primarily with reference to FIGS. 8L-8 r, while alternativeviews and/or embodiments of a lens assembly adjustment feature of theinvention are shown in FIGS. 1h, 1 i, 1 o, 1 p, 1 s, and 2L. In theembodiment of FIG. 8L it is seen that both the interior surface of lensretainer 82 and exterior surface 410 of barrel 40 are threadless andsubstantially smooth. Barrel 40 is slidably received in retainer 82.Barrel 40 may slide on interior wall 412 of retainer 82 or else barrel40 may slide on rails of 435. Preferably, barrel 40 and retainer 82 aremanufactured to tight or extremely tight tolerances so that barrel 40does not move substantially axially within retainer 82. In furtheraspects of the barrel and retainer system of FIG. 8L, lens retainer 82comprises adhesive receipt aperture 414 and an elongated adjustment pinaperture 416 coextensive with the axis of retainer 82. Variations ofaperture 414 and aperture 416 are shown throughout the views. Referringto further aspects of barrel 40, lens barrel 40 includes notch 420 whichin the embodiment of FIG. 1o is formed about the circumference of barrel40. Lens retainer 82 may further include key 424 which engages acomplementarily formed key 426 of barrel 40 so that barrel 40 isreceived in a desired radial orientation in lens retainer 82.

[0205] For adjusting and securing barrel 82 b within retainer 82, module10 having barrel 82 b nonfixedly secured therein is disposed in afixture 93 which may be of a type shown in FIGS. 8p and 8 q. Fixture 93may include one stationary member 93 s, one moveable member 93 m whichis moveable in small increments relative to stationary member 93 s, anda clamping device 93C which is actuatable for clamping module 10 withinfixture 93. When module 10 is disposed in fixture 93, pin 93 p offixture 93 passes through elongated pin receipt aperture 416 and engagesnotch of barrel 82 b. The lens-to image sensor distance is then finelyadjusted by adjusting the position of moveable member 93 m of fixture 93relative to the position of fixed member 93 s. In the fixture of FIGS.8p and 8 q, micrometer adjustment knob 93 k is actuated to precisionadjust the position of member 93 m relative to member 93 s. To aid inthe adjustment of the lens- to-barrel distance, module 10 may be poweredup, positioned to image a test target T, and adapted to be incommunication with a display 168 d (FIG. 10e) during the lens barreladjustment assembly step. An assembler may view an image of the testtarget displayed on display 168 d while adjusting the lens-to-imagesensor distance using fixture 93, and may determine whether a desireddistance is achieved based on the quality of the image displayed ondisplay 168 d. When a desired lens-to-image sensor distance is achieved,an operator disposes an adhesive in adhesive receipt aperture 414 sothat the adhesive bonds lens barrel 40 to retainer 82 in a fixedlysecure position. The adhesive may be e.g. a cyanocrylate based epoxyadhesive such as LOCTITE 401, LOCTITE UV 4304, LOCTITE 406, or LOCTITE4471 all available from LOCTITE Corporation of Rocky Hill, Conn. Thetest pattern which is imaged by module during the lens barrel adjustmentprocess may take on a variety of forms, but preferably comprises aplurality of fine print indicia so that the quality of focus can readilybe determined by observation of the displayed image. A dollar bill, forexample, may be utilized as a test target. The degree of focus can alsobe determined by image analysis of the image captured by processor 140described in connection with FIGS. 10a-10 e. For example, adetermination of whether an acceptable degree of focus has been achievedcan be made based on the value of a degree of focus signal as describedin commonly assigned U.S. Pat. No. 5,773,810 incorporated herein byreference.

[0206] Referring to further aspects of a threadless barrel lens assemblyadjustment system, pin receiving notch 420 formed on barrel 40 of FIG.8m is truncated as shown and does not extend circumferentially aboutbarrel 40. Further, adhesive receipt aperture 414 in the embodiment e.g.of FIGS. 8L is formed at a location of retainer 82 defined by aflattened planar interior surface 424. Flattened planar interior surface424 of retainer 82 operates as a key and engages complementarily formedflattened planar surface 426 of barrel 40 to align barrel 40 in adesired radial orientation within retainer 82. Key surface 426 can alsobe concave as shown in FIG. 8y, so that the retainer of adhesive bysurface 426 is improved so that a larger gap is defined between retainer82 and barrel 40. In addition to providing a keying function, thecomplimentary engaging surfaces 424 and 426 of barrel 40 and retainer 82operate to improve the security with which barrel 40 is held in placewithin retainer 82. The interface defined by planar surfaces 424 and 426operates to hold liquid adhesive in an isolated located during thecuring process, rather than allowing liquid adhesive to run anddissipate freely with retainer 82. The holding function is enhanced ifsurface 426 is concave. Because adhesive interface surface 426 of barrel40 and truncated notch 420 are spaced apart in the embodiment of FIGS.8L-8 m, adhesive material is not likely to invade notch 420 tocomplicate the adjustment process if further adjustment of barrel 40within retainer 82 is needed after application of adhesive material.Barrel 40 may be adjusted and secured within retainer 82 with use of afixture and a test image displaying display 168 d as describedpreviously in connection with FIGS. 8p and 8 q. In another aspect offinely adjustable threadless lens assembly barrel system, adhesivematerial may be deposited into pin aperture 416 as well as aperture 414,to increase the holding force with which barrel 40 is held in retainer82. In such an embodiment, retainer 82 effectively comprises a pair ofadhesive receiving apertures 414, 416. As shown in FIGS. 8L and 80,retainer 82 may include a plurality of rails including rails 435. Barrelmay be adapted to ride on rails 435. Rails 435 may be aligned inparallel with an axis of barrel while interior walls 412 of retainer 82may be drafted at a small angle (e.g. 0.5 degrees) so that supportassembly 80 can more easily be removed from a mold. Support assembly 80according to the invention can comprise black polycarbonate. Rails 435of which retainer may have several (e.g. 4) simplify the process ofmaking support 80 and help define an adhesive accommodating gap betweenbarrel 40 and retainer 82.

[0207] In an alternative embodiment of a finely adjustable barrel andholder system, both lens barrel 40 b and retainer 82 comprise threads asare shown generally by the embodiment of FIG. 8r. However, in a low costfinely adjustable threaded lens adjustment system, the threads of lensbarrel 82 b and retainer 82 are selected to be substantially coarse,loose tolerance threads such that barrel 40 is movable several micronsin the Z direction once it is received in retainer 82. An example of atype of course threads which are useful in finely adjustment barrel andholder system of the invention are Class 1 Coarse threads as designatedby the American National Standards Institute (ANSI). When substantiallycoarse threads are used in a finely adjustable threaded lens barrelsystem, barrel 40, in a rough adjustment step, is threaded into retainer82. In a fine adjustment step, barrel 40 is moved along the Z directionin lens retainer 82 without threading, taking advantage of the toleranceof the substantially coarse threads. A substantially coarsely threadedlens barrel, may have an adhesive receiving aperture 414 as shown in e.gFIG. 8L. A finely adjustable coarse threaded lens barrel system may alsoinclude an elongated pin receipt aperture 416 as described in connectionwith FIG. 8L and FIG. 2L which may also serve as an adhesive receivingaperture. Furthermore, a barrel 82 b in a finely adjustable coarsethreaded system may have a threadless section comprising a notch 410 asshown in FIG. 8r for engagement by pin 93 p. Pin 93 p may also engagethreads of barrel 82 b. When a desired lens to image sensor distance isachieved, adhesive may be applied to aperture 414, aperture 416, or toanother exposed interface between barrel 82 b and retainer 82 to securebarrel 82 n in a fixed position on retainer 82. A threaded barrel may beadjusted and secured within retainer 82 with use a fixture and testimage displaying display 168 d as described previously in connectionwith FIGS. 8p and 8 q.

[0208] In another embodiment of a finely adjustable barrel and retainersystem also described with reference to FIG. 8r, both barrel 40 andretainer 82 comprise a threaded section 460, 462 and an unthreadedsection 464, 466. Preferably, unthreaded sections 464, 466, aremanufactured to extremely tight tolerances to essentially prevent axialmovement (movement of barrel relative to axis, a) of barrel 82 b withinretainer 82. Threaded sections 460, 462 may comprise e.g. loosetolerance, course threads such as ANSI class 1 threads, or tighttolerance fine threads such as ANSI class 3 threads. If threadedsections 460, 462 include coarse threads, retainer 82 may includeadhesive receipt and pin receipt apertures 414, 416 to enable fineadjustment. If threaded sections 464, 466 include threads that aresufficiently fine, barrel 40 may be finely adjusted within retainer 82without use of pin 93 p and aperture 416. It will be seen that it isuseful to provide adhesive aperture 414 whether or not the adjustmentsystem includes threads. Further, it is useful to provide aperture 414on any location on retainer 82 in a threaded system irrespective thethread count and irrespective the span of thread sections 460, 462 onbarrel 40 and retainer 82.

[0209] G. Packaging of Electronics

[0210] Referring now to further aspects of module 10, e.g. module 10-1,the size of module 10 may be further reduced by mounting a partially orwholly “unpackaged” image sensor 32 onto first circuit board 14 a. Aprior art image sensor chip, or “image sensor” as referred to herein isshown in FIG. 8z. Image sensor 32 includes a ceramic or plasticsubstrate 32 s, integrated lead frames 32L, and a protective cover 32 c.Integrated surface mount or lead frames 32L extend rigidly from themajor body of image sensor 32 and are adapted to be soldered or socketedto printed circuit board 14 a.

[0211] While the prior art image sensor is durable, and easy to install,it also consumes substantial space. As a space conserving measure, imagesensor 32 of module 10 is may be an image sensor without at least one ofthe following elements being integrated into the image sensor chip: (a)ceramic substrate, (b) protective cover, or (c) leads. Mounting an imagesensor 32 to printed circuit board 14 b that does not include one ormore of the above components reduces the space consumed by image sensor32.

[0212] Imaging module 10 (e.g. module 10-1) consumes space in the X, Y,and Z dimensions as defined by FIG. 1a. It can be seen that mounting animage sensor 32 that does not have an integrated substrate 32 s and/orprotective cover 32 c integrated therein substantially reduces theZ-direction space consumption requirements of image sensor 32 andtherefore, of module 10-1. Mounting an image sensor 32 that does nothave rigid lead frames 32L integrated therein substantially reduces theX and Y dimension requirements of image sensor 32 and therefore, ofmodule 10-1.

[0213] The inventors found that one or more of the above image sensorcomponent parts can be eliminated from the image sensor chipincorporated in module 10 without substantially affecting the durabilityand performance of the module's imaging system. The image sensorintegrated substrate 32 s can be eliminated from an image sensor chipbecause image die 32 d of chip 32 can be mounted directly on printedcircuit board 14 a. The protective cover 32 c of image sensor 32 can bedeleted because image sensor 32, without an integrated cover 32 c can beadequately protected by support assembly 80. Further, rigid lead frames32L can be deleted from image sensor 32 because image sensor die 32 dcan be directly wire bound to printed circuit board 14 a or soldered toprinted circuit board 14 a Methods for mounting a “substrateless” imagesensor that does not include an integrated substrate 32 s to printedcircuit board 14 a are described with reference to FIGS. 8s and 8 t. Inthe embodiment depicted with reference to FIG. 8s, image sensor die 32 dis deposited directly onto printed circuit board 14 a and wirebonded toprinted circuit board 14 a. Wirebonds 32 w can comprise for, example,Aluminum (AL) or Gold (AU). In the embodiment depicted with reference toFIG. 8t image sensor die 32 d is structurally and electrically connectedto printed board 14 a via solder bumps 32 b interposed between die 32 dand printed circuit board 14 b. Electronic packaging firms such as TaskMicroelectronics, Inc. of Montreal, Ontario specialize in mountingsubstrateless silicon based chips without lead frames directly ontoprinted circuit boards.

[0214] An alternative method for reducing the Z-direction spaceconsumption of module 10 in the area forward of printed circuit board 14a is described with reference to FIG. 8u. As seen in FIG. 8u imagesensor 32 can be face mounted to printed circuit board such that aperiphery of face 32 f, or top surface of image sensor 32 is benchedonto a back side 14 a-r of circuit board 14 a provided that an imagesensor window 14 w is formed in printed circuit board 14 a. Image sensor32 in the embodiment of FIG. 8u can be a typical “packaged” image sensoras is illustrated in FIG. 8s having an integrated substrate, aprotective cover, and lead frames or else image sensor 32 can be of atype that does not include one or more elements selected from the groupcomprising an integrated substrate, protective cover or lead frame.Solder bumps 32 b may electronically and structurally secure imagesensor 32 to PCB 14 a.

[0215] Miniature imaging modules as described herein will find increaseduse in battery operated devices including cordless bar code readers,PDAs and cellular telephones. There is therefore, increased motivationfor making modules as energy efficient as is possible so as to increasethe battery life of a battery which may be adapted to power module 10.

[0216] In the embodiment shown in FIG. 8L an illumination circuit board14 b of module 10-24 is adapted with a heat sink which draws heat awayfrom LEDs 16 and 18 so that LEDs 16 and 18 operate at improvedefficiency. A cross-section of an illumination circuit board is shown inFIG. 8t. A typical illumination circuit board of module 10-24, as shownin FIG. 8L may include seven layers, including three insulatingfiberglass layers 14 f 1, 14 f 2, and 14 f 3 interposed betweenconductive layers, typically comprising copper. As seen in FIG. 8xillumination circuit board 14 b may include one or more heat sink tabs14T1 and 14T2 extending therefrom. In the formation of a heat sink tab14T1, one or more of the copper layers may be extended outwardly fromthe edge e of the circuit board as is indicated by copper layer 14 c 2.A fiberglass layer abutting extended layer 14 c 2 may also be extendedfrom edge e for supporting the extended copper layer. Extended copperlayer 14 c 2 defining tab T1 may be electrically connected to a groundtracing of printed circuit board 14 b. Exposing a conductive coppersurface of tab T1 to air removes heat from circuit board 14 a resultingin increased efficiency and expected life in the operation of LEDs 16and 18. Furthermore, one or more tabs 14T1 and 14T2 of module 10-24 canbe attached to a heat sink structure 15 as is shown in FIG. 8w. Heatsink structure 15 which is adapted to be situated in the housing of theimaging device in which module 10-24 is installed comprises a conductivematerial such as copper or aluminum. Heat sink structure 15 increasesthe surface area formed by the combination of tab 14T1 and structure 15and thereby increases the amount of heat that is removed from circuitboard 14 b. In another heat sinking apparatus a heat sink structure isconnected to a post or posts 84 as indicated in connection with FIG. 2h.Member 14 p attached to posts 84 can be a heat sink structure comprisedof a thermally conductive but electrically insulating material such asBoralloy Pyrolytic Born Nitride from Advanced Ceramics Corp. ofCleveland, Ohio.

[0217] An important feature of the invention as embodied by module 10-9is that essentially all the illumination elements of a reader in whichmodule 10-9 is to be incorporated can be included on a single circuitboard shown as being provided by PCB 14 a. This is in contrast to thedesign of the prior art reader shown in FIG. 11 in which illuminationelements and image sensing elements are spread out over several circuitboards. In the prior art device shown in FIG. 11, an aiming illuminationsource 53 is mounted to a first circuit board 54, illumination LEDs 55are mounted to a second circuit board 56, while image sensor 32 ismounted to first circuit board 54. The device of FIG. 11 furtherincludes a third circuit board 60 carrying signal processing anddecoding electrical hardware components. The assembly of a module ofthis prior art design is difficult and requires material components notrequired by the design of the present invention including circuit boards54 and 56 and electrical connectors between the circuit boards such asconnectors 57 a and 57 b. Providing a single circuit board that carriesan image sensor, illumination LEDs, and aiming LEDs significantlysimplifies assembly, reduces material consumption and thereby reducesthe overall cost of producing the module. Another important aspect ofthe invention as embodied by module 10-9, in one embodiment, is thatessentially all electronic circuitry supporting the data processingoperations required of module 10 are located on single, full functionPCB 14 a, including circuitry for processing signals generated fromimage sensor 32, circuitry for capturing image data into a memorydevice, circuitry for decoding and/or recognizing indicia represented incaptured image data. Circuitry for supporting serial transfers of datato peripheral devices may also be carried by PCB 14 a.

[0218] The all in one PCB arrangement of the present invention is incontrast to the traditional design in the prior art wherein circuitryfor processing signals from an image sensor, circuitry for capturing anddecoding image data and circuitry supporting serial interfacing withexternal devices are spread out over more than one circuit board.

[0219] In the design of the prior art reader shown in FIG. 11, a firstvertically oriented circuit board 56 is provided for carrying circuitryfor processing signals generated by an image sensor 32 and a secondhorizontally oriented circuit board 60, known as a “mother board” isprovided for carrying circuitry for storing image data and for decodingsymbologies. The one PCB design of the present invention providesnumerous advantages over the two PCB design of the prior art. Themultiple circuit board arrangement of the prior art requires a complexassembly procedure wherein the first circuit board 58 is mounted to afirst internal structure of the reader in which it is incorporated, thesecond circuit board is mounted to a second internal structure of thereader, and then the two circuit boards are electrically connected. Theseparate horizontal and vertical orientations of the two circuit boards58 and 60 is inefficient in terms of space consumption and imposesrestrictions on the configurations of housings in which the readeroptical and electrical components may be incorporated. The one fullfunction PCB design of the present invention does not exhibit thesedisadvantages.

[0220] In accordance with a feature of one embodiment of the inventiondescribed with reference to e.g. modules 10-1 through module 10-21,essentially all of the electrical signal processing components describedwith reference to FIG. 10a may be carried by a single circuit board,circuit board 14 a, as is indicated by dashed-in border 14 a of FIGS.10a-10 e. In order to incorporate essentially all of the electricalsignal processing components of FIG. 10a onto a single PCB 14 a, it isnormally necessary to integrate several electrical components into areduced number of electrical components. For example, using knownintegrated circuit fabrication techniques, components 142, 144, 146, and147 and interfaces 137, 137′, and 137″ can be incorporated in a singleintegrated circuit chip of reduced size. Further, as explained in anarticle by Eric R. Fossum entitled Digital Camera System on a Chip, IEEEComputer Society (IEEE Micro), Volume 18, Number 3, May/June 1998, imagesensor 132, signal processing components 135, 136, and components 142,144, 146, 147, 137, 137′, and 137” may be incorporated in a singleintegrated circuit of reduced size.

[0221] H. Applications, Operating Environments, and Control CircuitFunctionality

[0222]FIGS. 9a-k show examples of types of housings in which the modulesof the present invention may be incorporated. FIGS. 9a and 9 b show a 1Doptical reader 110-1, while FIGS. 9c-9 h show 2D optical readers 110-2,110-3, and 110-4. Readers 110-1, 110-2, 110-3 comprise the form factorof a gun-styled reader while reader 110-4 compresses the form factor ofwhat is often referred to portable data terminal (PDT). Referring toadditional readers, reader 110-5 of FIG. 9j comprises the form factor ofa mobile telephone, reader 110-6 of FIG. 9j comprises the form of aportable data assistant (PDA) while reader 110-7 of FIG. 9k comprisesthe form factor of a finger-worn reader, sometimes referred to as a“ring scanner.” Housing 111 of each of the optical readers 110-1 to110-7 is adapted to be graspable by a human hand (or worn on a finger)and has incorporated therein at least one trigger switch 113 t foractivating image capture and decoding and/or image capture and characterrecognition operations. Readers 110-1, 110-2, and 110-3 includehard-wired communication links 178 for communication with externaldevices such as other data collection devices or a host processor, whilereaders 110-4 to 110-7 include an antenna 180 (seen in FIGS. 9h and 9 ionly) for providing wireless communication with an external device suchas another data collection device or a host processor.

[0223] It will be seen that modules 10-1 to 10-8 in particular becauseof their notably small exemplary dimensions (0.810×0.450×0.560) orsubstantially smaller can be incorporated in virtually any smallinstrument housing, for example, a calculator, a pen, a medicalinstrument, and a watch in a addition to any of the housings describedin FIGS. 9a-9L.

[0224] An embodiment of module 10-1 shown as incorporated an alternativemobile phone housing is shown in FIG. 9m. In FIG. 9n, module 10-1 isincorporated into an integrated housing of a writing instrument providedby a pen. The pen reader 110-9 of FIG. 9n includes a housing 111 havingincorporated therein module 10-1, a processor assembly 130 including acontrol circuit 140 as described in connection with FIG. 10a, which isresponsive to actuation of redundant triggers 113 t disposed to beaccessible from an exterior of housing 111, an ink reservoir (not shown)and a head-unit (e.g. a ball point ink dispenser) including tip 960 fordispensing ink from the reservoir onto a sheet of paper. Housing headsection 111 h can be made detachably attachable with the remainder ofhousing 111 go that housing 111 is a two piece housing or else headsection 111 h can be integrated into the remainder of housing 111 sothat housing 111 is a one-piece housing. Combining imaging module 10-1configured by circuit 140 to have dataform-reading functionality andwriting functionality in a common housing 111 is highly useful in thatdata form readers and writing instruments are devices which are bothused extensively in data collection applications. A module 10 accordingto the invention an also be incorporated in, for example medicationdispensing equipment, patient monitors of all forms, access controlequipment, integrated recognition equipment to add feature recognition(such as facial, hand, or retinal). As well, such modules may findapplication in household appliances such as sewing machines, andmicrowaves where indicia can provide useful functionality to the user.

[0225] Module e.g. 10-1 can be mounted to an internal member of ahousing 111 or another rigid member by screwing set screws through thehousing member and through screw holes 810 of module 10-1 described inconnection with FIG. 1h and 1 i. Further, brass threaded inserts can bedisposed in holes 810 so that holes receive machine screws. In addition,module 10-1 includes connector 930 for receiving a flex connector toprovide electrical communication with circuitry of reader 110 e.g. a“mother board” 60 as in the prior art reader FIG. 11. Still further,support posts 84 can be utilized to mount, stabilize, or support module10-1 within a reader housing. As discussed previously module includingposts 84 can have post ends 84 e that protrude extensively from circuitboard 14 a. These post ends 84 e can be plugged into sockets 910 formedon a rigid member of members of an interior of a reader housing 111 oron another rigid member outside of a housing to mount, stabilize orsupport module e.g. 10-1. Additional posts 84 a, as shown in FIG. 2k canbe interposed between sockets 910 and posts 84. A socket containingrigid member 916 may be provided by a housing wall as is indicated bythe embodiment of FIG. 9o.

[0226] In addition to the above elements, readers 110-3, 110-4, 110-5and 110-6, each include a display 182 for displaying information to auser and a keyboard 184 for enabling a user to input commands and datainto the reader.

[0227] Any one of the readers described with reference to FIGS. 9a-9 kmay be mounted in a stationary position as is illustrated in FIG. 9Lshowing a generic optical reader 110 docked in a scan stand 190. Scanstand 190 adapts portable optical reader 110 for presentation modescanning. In a presentation mode, reader 110 is held in a stationaryposition and an indica bearing article is moved across the field of viewof reader 110. Of course, only module 10 described herein can be placedin a scan stand 190 or may otherwise be mounted (replaceably or fixedly)in a stationary position.

[0228] Block diagrams of electrical circuit control configurations whichmay be wholly or partially incorporated in module 10 or used incombination with circuitry of module 10 are now described.

[0229] Referring to the block diagram of FIG. 10a, imaging deviceprocessor assembly 130 includes an illumination assembly 121 forilluminating a target area T, such as a substrate bearing a 1D or 2D barcode symbol or a text string, and an imaging assembly 133 for receivingan image of object T and generating an electrical output signalindicative of the data optically encoded therein. Illumination assembly121 may, for example, include an illumination source assembly e.g. 16,18, together with an illuminating optics assembly 124, such as one ormore lenses 25, diffusers 27, wedges 28, reflectors 640 or a combinationof such elements, for directing light from light source 16, 18 in thedirection of a target object T. Illumination assembly 121 may comprise,for example, laser or light emitting diodes (LEDs) such as white LEDs orred LEDs. Illumination assembly 121 may include target illuminationoptics for projecting an aiming pattern e.g. 630, 631, 647 on target T.Illumination assembly 121 may be eliminated if ambient light levels arecertain to be high enough to allow high quality images of object T to betaken. Illumination assembly 121 may also be located remote from imagingdevice housing 111, at a location so as to eliminate or reduce specularreflections. Imaging assembly 133 may include an image sensor 32, suchas a color or monochrome 1D or 2D CCD, CMOS, NMOS, PMOS, CID or CMDsolid state image sensor, together with an imaging optics assembly 40for receiving and focusing an image of object T onto image sensor 32.Features and advantages associated with incorporating a color imagesensor in an imaging device, and other control features which may beincorporated in control circuit 140 are discussed in greater detail inU.S. Ser. No. 09/904,697, filed Jul. 13, 2001, entitled “An OpticalReader Having a Color Imager” incorporated herein by reference. Thearray-based imaging assembly shown in FIG. 10a may be replaced by alaser array based imaging assembly comprising one or more laser sources,a scanning mechanism, emit and receive optics, at least onephotodetector and accompanying signal processing circuitry.

[0230] Imaging device processor assembly 140 of the embodiment of FIG.10a includes programmable control circuit 140 which preferably comprisesan integrated circuit microprocessor 142 and field programmable gatearray (FPGA 144). The function of FPGA 144 could also be provided byapplication specific integrated circuit (ASIC), which is also consideredto be designated by reference character 144 in FIG. 10a-10 e. ICmicroprocessor 142 can be e.g. a Motorola Power PC, 82E ICMicroprocessor as an INTEL, Strong Arm, SA1110. FPGA 144 may be e.g. aXilinx, SPARTAN, XCSXXXX FPGA IC.

[0231] Processor 142 and FPGA 144 are both programmable control deviceswhich are able to receive, output and process data in accordance with astored program stored in memory unit 145 which may comprise such memoryelements as a volatile or non-volatile read/write random access memoryor RAM 146, 146-1 and an erasable read only memory or EROM 147, 147-1.Memory 145 may also include one or more long term non-volatile memorystorage devices (148, 145). For example, storage device 148, 145 mayinclude e.g. a hard drive, or floppy disk to which data can be writtento or read from. Storage device 148, 145 can be of a type that issecurely installed in housing 111 (e.g. a hard drive) or can be of atype that can be removed from housing 111 and transported (e.g. floppydisk). Memory 145 can include what is referred to as a “flash” memorydevice. Several standardized formats are available for such flash memorydevices including: “Multimedia” (MMC), “Smart Media,” “Compact Flash,”and “Memory Stick.” Although the transfers of data between processor 140and a flash memory device normally involve “blocks” of data and not“bytes” of data as in standardly known non-volatile RAM device, theoperation of a “flash” memory device is similar to a standardly knownnon-volatile RAM memory device. Accordingly, a flash memory device canbe considered to be represented by the one or more RAM blocks 146 ofFIGS. 10a-10 e. As is well known, flash memory devices are commonlyavailable in a form that allows them to be removed from a first deviceand transported to a second device, e.g. between device 110 and device168. Flash memory devices are particularly well suited for storing andarchiving image data.

[0232] Processor 142 and FPGA 144 are also both connected to a commonbus 149-1 through which program data and working data, including addressdata, may be received and transmitted in either direction to anycircuitry that is also connected thereto. Processor 142 and FPGA 144differ from one another, however, in how they are made and how they areused.

[0233] More particularly, processor 142 is preferably a general purpose,off-the-shelf VLSI integrated circuit microprocessor which has overallcontrol of the circuitry of FIG. 8a, but which devotes most of its timeto decoding decodable image data such as symbology or text characterdata stored in RAM 146, 146-1 in accordance with program data stored inEROM 147, 147-1. FPGA 144, on the other hand, is preferably a specialpurpose VLSI integrated circuit, such as a programmable logic or gatearray, which is programmed to devote its time to functions other thandecoding image data, and thereby relieve processor 142 from the burdenof performing these functions.

[0234] The actual division of labor between processor 142 and FPGA 144will naturally depend on the type of off-the-shelf microprocessors thatare available, the type of image sensor which is used, the rate at whichimage data is output by imaging assembly 133, etc. There is nothing inprinciple, however, that requires that any particular division of laborbe made between processors 142 and 144, or even that such a division bemade at all.

[0235] With processor architectures of the type shown in FIG. 10a, atypical division of labor between processor 142 and FPGA 144 will be asfollows. Processor 142 is preferably devoted primarily to such tasks asdecoding image data in response to trigger 113 t being activated, oncesuch data has been stored in RAM 146, 146-1, controlling the outputtingof user perceptible data via aural output 114A, good read indicator 114g and display 114 d and, recognizing characters represented in storedimage data according to an optical character recognition (OCR) scheme inresponse to an actuation of trigger 113 t.

[0236] FPGA 144 is preferably devoted primarily to controlling the imageacquisition process, the A/D conversion process and the storage of imagedata, including the ability to access memories 146-1 and 147-1 via a DMAchannel. FPGA 144 may also perform many timing and communicationoperations. FPGA 144 may, for example, control the illumination of LEDs16,18, the timing of image sensor 132 and an analog-to-digital (A/D)converter 136-1, the transmission and reception of data to and from aprocessor system external to assembly 130, through an RS-232, a networksuch as an ethernet, a serial bus such as USB, a wireless communicationlink (or other) compatible I/O interface as is indicated by interface137-2. FPGA 144 may also control the outputting of user perceptible datavia an output device, such as aural output device 114 a, a good read LED114 g and/or a display monitor which may be provided by a liquid crystaldisplay such as display 114 d. Control of output, display and I/Ofunctions may also be shared between processors 142 and 144, assuggested by bus driver I/O interface 137-3 or duplicated, as suggestedby microprocessor serial I/O interface 137-1 and interface 137-2. Asexplained earlier, the specifics of this division of labor is of nosignificance to the present invention. The imaging device described withreference to FIG. 10a can be adapted for use in connection with theinvention by providing a display, e.g. display 168 d that is external tohand-held housing 111, but is in communication with control circuit 140.

[0237]FIG. 10b shows a block diagram exemplary of an optical imagingdevice which is adapted to easily receive user-input controlinstructions resulting in a change in an operating program of a imagingdevice. In addition to having the elements of single state imagingdevice circuit of FIG. 10a, imaging device 110 b includes a keyboard 113k for inputting data including instructional data and a display 114 dfor displaying text and/or graphical information to an operator.Keyboard 113 k may be connected to bus 148-1, FPGA 144 or to processor142 as indicated in FIG. 2b. Display 114 d may be connected to FPGA 144,to processor 142 or to system bus 148-1 as is indicated in theparticular embodiment of FIG. 10b.

[0238] An operator operating optical imaging device 110 b can reprogramimaging device 110 b in a variety of different ways. In one method forreprogramming imaging device 110-b, an operator actuates a controlbutton of keyboard1 113 k which has been pre-configured to result in thereprogramming of imaging device 110 b. In another method forreprogramming imaging device 110 b an operator actuates control of aprocessor system not integral with imaging device 110 b to transmit aninstruction to reprogram imaging device 110 b. According to anothermethod for reprogramming imaging device 110 b, an operator moves imagingdevice 110 b so that a “menu symbol” is in the field of view of imagesensor 32 and then activates trigger 113 t of imaging device 110 b tocapture an image representation of the menu symbol. A menu symbol is aspecially designed bar code symbol which, when read by an appropriatelyconfigured optical imaging device results in a imaging device beingprogrammed. The reprogramming of an optical imaging device with use of amenu symbol is described in detail in commonly assigned U.S. Pat. No.5,965,863 incorporated herein by reference. Because the second and thirdof the above methodologies do not require actuation of a imaging devicecontrol button of keyboard 113 k but nevertheless result in a imagingdevice being reprogrammed, it is seen that imaging device 110 may bekeyboardless but nevertheless reprogrammable. It will be seen that thesecond or third of the above methodologies can be adapted for selectingoperating modes described herein.

[0239] A typical software architecture for an application operatingprogram typically executed by an optical imaging device as shown in FIG.10b is shown in FIG. 10f depicting a memory map of a program stored inprogram memory 147-1. Application operating program 160 adapts a imagingdevice for a particular application. Three major applications orfunctions for an optical imaging device imaging device having imagecapture capability are: (1) comprehensive decoding; (2)data transfer;and (3) image capture, e.g. signature capture. In a comprehensivedecoding application, imaging device 110 may preliminarily analyze andthen decode a message corresponding to a bar code symbol or OCRdecodable text character. In a data transfer application, imaging device110 uploads character text files or image files to a processor systemlocated externally relative to imaging device housing 111. In asignature capture application, imaging device 110 may capture an imagecorresponding to a scene having a signature, parse out from the imagedata that image data corresponding to a signature, and transmit thecaptured signature data to another processing system. It is seen thatthe third of such applications can be carried out by an optical imagingdevice imaging device that is not an optical imaging device decoderequipped with decoding capability. Numerous other application operatingprograms are, of course possible, including a specialized 1D decodingapplication, a specialized 2D bar code decoding algorithm, a specializedOCR decoding application which operates to decode OCR decodable textcharacters, but not bar code symbols.

[0240] Referring now to specific aspects of the software architecture ofan operating program 160, program 160 includes an instruction section162, and a parameter section 164. Further, instruction section 162 mayinclude selectable routine section 162 s. Instructions of instructionsection 162 control the overall flow of operations of imaging device110. Some instructions of instruction section 162 reference a parameterfrom a parameter table of parameter section 164. An instruction ofinstruction section 62 may state in pseudocode, for example, “setillumination to level determined by [value in parameter row x].” Whenexecuting such an instruction of instruction section 162, controlcircuit 140 may read the value of parameter row 164 x. An instruction ofinstruction section 162 may also cause to be executed a selectableroutine, that is selected depending on the status of a parameter valueof parameter section 164. For example, if the application program is abar code decoding algorithm then an instruction of instruction section162 may state in pseudocode, for example, “launch Maxicode decoding ifMaxicode parameter of parameter row 164 y is set to “on.” When executingsuch an instruction, control circuit 140 polls the contents of row 164 yof parameter section 164 to determine whether to execute the routinecalled for by the instruction. If the parameter value indicates that theselectable routine is activated, control circuit 140, executes theappropriate instructions of routine instruction section 162 s to executethe instruction routine.

[0241] It is seen, therefore, that the above described softwarearchitecture facilitates simplified reprogramming of imaging device 110.Imaging device 110 can be reprogrammed simply by changing a parameter ofparameter section 164 of program 160, without changing the subroutineinstruction section 162 s or any other code of the instruction section162 simply by changing a parameter of parameter section 164. Theparameter of a parameter value of section 162 can be changed byappropriate user control entered via keyboard 113 k, by reading a menusymbol configured to result in a change in parameter section 164, or bydownloading a new parameter value or table via a processor system otherthan system 140 as shown in FIGS. 10a and 10 b. The reprogramming ofimaging device 110 b can of course also be accomplished by downloadingan entire operating program including sections 162 and 164 from aprocessor system other than a system as shown in FIGS. 10a and 10 b.

[0242] Another architecture typical of an optical imaging device whichmay be configured in accordance with the invention is shown in FIG. 10c.Imaging device 110 c comprises a control circuit 140 having a processorsystem 140 s 1, and an integrated host processor system 140 s 2 whichincludes host processor 140 hp and an associated memory 145-2. “Hostprocessor system” herein shall refer to any processor system whichstores a imaging device application operating program for transmissioninto a processor system controlling operation of a imaging deviceimaging system 133 or which exercises supervisory control over aprocessor system controlling operation of a imaging device imagingsystem 133, or which stores in its associated memory more than oneapplication operating program that is immediately executable onreception of a command of a user. In a imaging device having twoprocessors such as processor 142 and processor 140 hp, processor 142 istypically dedicated to processing image data to decode decodableindicia, whereas processor 140 hp is devoted to instructing processor142 to execute decoding operations, receiving inputs from trigger 113 tand keyboard 113 k, coordinating display and other types of output byoutput devices 114 d, 114 g, and 114 a and controlling transmissions ofdata between various processor systems.

[0243] In architectures shown in FIG. 10c having dedicated decodingprocessor system 140 s 1 and a powerful, supervisory host processorsystem 140 s 2, host processor system 140 s 2 commonly has storedthereon an operating system, such as DOS WINDOWS or WINDOWS, or anoperating system specially tailored for portable devices such as,WINDOWS CE available from Microsoft, Inc. In the case that hostprocessor system 140 s 2 includes an operating system such as DOS orWINDOWS CE, the instruction section and parameter section of theoperating program controlling the operation of host processor system 140s 2 normally are programmed in a high level programming language andassembled by an assembler before being stored in memory 147-2 andtherefore may not reside in consecutive address locations as suggestedby program 160 shown in FIG. 10f. Nevertheless, host processor system140 s 2 having an operating system integrated thereon can readilyassemble an operating program into such a form for loading into anexternal processor system that does not have an operating system storedthereon.

[0244] Referring to further aspects of imaging devices 110 a, 110 b, and110 c at least one I/O interface e.g. interface 137-1, 137-2, and 137-3facilitates local “wired” digital communication such as RS-232,ethernet, serial bus including Universal Serial Bus (USB), or localwireless communication technology including “Blue Tooth” communicationtechnology. At least one I/O interface, e.g. interface 137-3, meanwhile,facilitates digital communication with remote processor assembly 188-1in one of an available remote communication technologies includingdial-up, ISDN, DSL, cellular or other RF, and cable. Remote processorassembly 88-1 may be part of a network 188N of processor systems assuggested by assemblies 188-2, 188-3, and 188-4 links 188L and hub 188He.g. a personal computer or main frame computer connected to a network,or a computer that is in communication with imaging device 10 c only andis not part of a network. The network 88N to which assembly 188-1belongs may be part of the internet. Further, assembly 188-1 may be aserver of the network and may incorporate web pages for viewing by theremaining processor assemblies of the network. In addition to being incommunication with imaging device 110 c, assembly 188-1 may be incommunication with a plurality of additional imaging devices 110′ and110″. Imaging device 110 c may be part of a local area network (LAN).Imaging device 110 may communicate with system 188-1 via an I/Ointerface associated with system 188-1 or via an I/O interface 188I ofnetwork 188N such as a bridge or router. Further, a processor systemexternal to processor system 140 such as processor system 170 s may beincluded in the communication link between imaging device 110 andassembly 188-1. While the components of imaging devices 110 a, 110 b,and 110 c are represented in FIGS. 10a-10 c as discreet elements it isunderstood that integration technologies have made it possible to formnumerous circuit components on a single integrated circuit chip. Forexample, with present fabrication technologies, it is common to formcomponents such as components 142, 140, 146-1, 147-1, 137-2, and 137-1on a single piece of silicone.

[0245] Furthermore, the number of processors of imaging device 110 isnormally of no fundamental significance to the present invention. Infact if processor 142 is made fast enough and powerful enough specialpurpose FPGA processor 144 can be eliminated. Likewise, referring toimaging device 110 c, a single fast and powerful processor can beprovided to carry out all of the functions contemplated by processors140 hp, 142, and 144 as is indicated by the architecture of imagingdevice 110 e of FIG. 10e. Still further, it is understood that ifimaging device 110 includes multiple processors the processors maycommunicate via parallel data transfers rather than via the serialcommunication protocol indicated by serial buses 149-1 and 149-2. Inaddition, there is no requirement of a one-to-one correspondence betweenprocessors and memory. Processors 142 and 140 hp shown in FIG. 10c couldshare the same memory, e.g. memory 145-1. A single memory e.g. memory45-1 may service multiple processors e.g. processor 142 and processor140 hp.

[0246] Referring to the embodiment of FIG. 10d, it is seen that it isnot necessary that the entirety of electrical components of an opticalimaging device 110 be incorporated in a portable device housing 111. Theelectrical components of imaging device 100 are spread out over morethan one circuit board that are incorporated into separate devicehousings 111 and 171. It is understood that circuitry could be spreadout into additional housings. Control circuit 140 in the embodiment ofFIG. 10d is incorporated entirely in the housing 171 that isnon-integral with portable device housing 111. Housing 171 is shown asbeing provided by a personal computer housing, but could also beprovided by another type of housing such as a cash register housing, atransaction terminal housing or a housing of another portable devicesuch as housing 111. At least one operating program for controllingimaging assembly 133 and for processing image signals generated fromimaging assembly 133 is stored in EROM 147-1 located within PC housing171. For facilitating processing of signals generated from imagingassembly 133 by a processor system that is not integrated into portablehousing 111 a high speed data communication link should be establishedbetween imaging assembly 133 and processor system 140. In the embodimentof FIG. 10d, I/O interfaces 137-4 and 137-5 and communication link 139may be configured to operate according to the USB data communicationprotocol. The configuration shown in FIG. 10d reduces the cost, weight,and size requirements of the portable components of imaging device 110d, which in imaging device 110-4 are the components housed withinportable housing 111. Because the configuration of FIG. 10d results infewer components being incorporated in the portable section 111 ofimaging device 110 d that are susceptible to damage, the configurationenhances the durability of the portable section of imaging device 110-4delimited by housing 111.

[0247] The control circuit 140 as shown in the embodiment of FIG. 10dcan be in communication with more than one “shell” processorless imagingdevice comprising a imaging device housing and a imaging devicecircuitry shown by the circuitry within dashed housing border 111 ofFIG. 10d. In the case that a control circuit as shown in FIG. 10dservices many “shell” imaging devices or processor-equipped imagingdevices input/output port 137-5 should be equipped with multiplexingfunctionality to service the required data communications betweenseveral imaging devices and/or shell imaging devices and a singleprocessor system.

[0248] The imaging device communication system of FIG. 10e has aphysical layout identical to imaging device 110 d, but is optimized fora different operation. System 167 is a communication system in whichimaging device processor system 140 communicates with a nonintegratedlocal host processor assembly 168 provided by a personal computer 168having a PC housing 171, a processor system 170 s, a storage device 175(e.g. hard drive), a keyboard 168 k, a mouse 168 m, and a display 168 d.Provided that link 167L is a high speed communication link,nonintegrated local host processor system 170 s could be programmed toprovide functioning identical to processor system 140 s of imagingdevice 110 d. However, because imaging device 110 e comprises anintegrated processor system 140 such programming is normallyunnecessary, although as described in copending application Ser. No.09/385,597, incorporated by reference herein it is useful to configureprocessor system 140 communication with a host processor system e.g. 170s so that certain components of imaging device 110 such as trigger 113 tcan be controlled remotely by host processor system 170 s, which in oneembodiment is nonintegrated. Accordingly, in imaging device-hostcommunication systems as shown in FIG. 10e nonintegrated host processorassembly 168 typically is programmed to provide functions separate fromthose of the imaging device processor systems described in connectionwith FIGS. 10a-10 d.

[0249] As described in U.S. Pat. No. 5,965,863, incorporated herein byreference, one function typically provided by nonintegrated local hostprocessor system 70 s is to create operating programs for downloadinginto imaging device 110. Processor system 170 s typically has anoperating system incorporated therein, such as WINDOWS, which enables anoperator to develop operating programs using a graphical user interface,which may be operated with use of a pointer controller 168 m.Nonintegrated local processor system 170 s also can be configured toreceive messages an/or image data from more than one imaging device,possibly in a keyboard wedge configuration as described in U.S. Pat. No.6,161,760, incorporated herein by reference. It is also convenient toemploy processor system 170 for data processing. For example aspreadsheet program can be incorporated in system 170 s which is usefulfor analyzing data messages from imaging device 110 e. An imageprocessing application can be loaded into system 170 s which is usefulfor editing, storing, or viewing electronic images received from imagingdevice 110 e. It is also convenient to configure imaging device 110 e tocoordinate communication of data to and from a remote processor assemblysuch as assembly 188-1. Accordingly processor assembly 168 typicallyincludes I/O interface 174-2 which facilitates remote communication witha remote processor assembly, e.g. assembly 188-1 as shown in FIG. 10c.

[0250] While the present invention has been described with reference toa number of specific embodiments in order to set forth the best modethereof, it will be understood that the spirt and scope of the presentinvention should be determined with reference to the following claims.

We claim:
 1. An optical reader imaging module comprising: a firstcircuit board carrying a two dimensional image sensor; a second circuitboard spaced forwardly of said first circuit board; a support assemblyat least partially interposed between said firs circuit board and saidsecond circuit board; an aiming system for projecting an aiming linecomprising aiming LEDs, said aiming LEDs being mounted on said firstcircuit board; an illumination system for projecting a substantiallyuniform illumination pattern on a target area, said is illuminationsystem comprising illumination LEDs mounted on said second circuitboard; wherein said aiming LEDs are selected to emit light in adifferent visible color relative to a visible color emitted by saidillumination LEDs so that said aiming pattern is in color contrastrelative to said illumination pattern.
 2. The imaging module of claim 1,wherein said aiming LEDs are selected to emit visible light in the greenvisible wavelength band, and wherein said illumination LEDs are selectedto emit light in the red visible wavelength band.
 3. The imaging moduleof claim 1, wherein said illumination LEDs are selected to emit white,light, and wherein said aiming LEDs are selected to emit light in anarrow visible color band of wavelengths within a white light wavelengthband.
 4. The imaging module of claim 1, wherein said aiming system andsaid illumination system comprise a common optical plate abutted againsta front of said second circuit board.
 5. the imaging module of claim 1,wherein said aiming system includes an aperture disposed forwardlyrelative to each of said plurality of LEDs, and imaging optics disposedoptically forwardly relative to each aperture m for projecting anaperture image into a target area.
 6. The imaging module of claim 1,wherein said module includes a color filter disposed in said module, forpreventing light in an emission color of said aiming light sources fromreaching said two dimensional image sensor.
 7. An optical reader forreading target indicia, said optical reader comprising: an imagingsubsystem including an image sensor and a lens assembly for focusinglight on said image sensor; a control circuit in communication with saidimaging subsystem; and an illumination subsystem, in communication withsaid control circuit, said illumination subsystem comprising at leastone multiple color-emitting light source, said at least one multiplecolor-emitting light source having at least two independently drivablelight emitting elements.
 8. The optical reader of claim 7, wherein saidcontrol circuit is adapted to sense a condition present relative to saidtarget, and wherein said control circuit is further adapted to change acolor emitted by said multicolor light source in response to said sensedcondition.
 9. The optical reader of claim 8, wherein said imaging systemincludes a color image sensor, wherein said control circuit is adaptedto sense a color present in said target, and wherein said controlcircuit is further adapted to change a color emitted by said multiplecolor-emitting source in response to said sensed color condition. 10.The optical reader of claim 7, wherein said multiple color-emittinglight source of said illumination subsystem is an illumination lightsource.
 11. The optical reader of claim 7, wherein said multiplecolor-emitting light source of said illumination light source is anaiming light source.
 12. The optical reader of claim 7, wherein saidcontrol circuit is adapted to change a color emitted by said at leastone multiple color-emitting light source when an operating mode of saidreader changes or is changed.
 13. The optical reader of claim 7, whereinsaid control circuit is adapted to change a color emitted by said atleast one multiple color-emitting light source when an operating mode ofsaid reader changes from a decoding attempt mode to a successful decodemode, so that a change in color emitted by said at least multiplecolor-emitting light source indicates a good read.
 14. The opticalreader of claim 7, wherein said multicolor illumination light source, isa multiple color-emitting LED of the type having a plurality of LEDdies, each being independently drivable, wherein said control circuitestablishes a certain color emitted by said multiple color-emittinglight source by presenting a set of LED die driver signals to said LEDdies.
 15. The optical reader of claim 7, wherein said multiplecolor-emitting light source is an illumination light source, saidcontrol circuit is adapted to change a color emitted by said multicolorLED from a first color to a second color prior to a second decodeattempt, if a first decode attempt using said first color isunsuccessful.
 16. The optical reader of claim 15, wherein said controlcircuit is adapted to save signals establishing said second color ifsaid second decode attempt is successful, said control circuit furtherbeing adapted to present said signals resulting in a second decode mode.17. An optical reader comprising: an imaging subsystem including a twodimensional image sensor and a lens assembly for focusing light ontosaid image sensor; a control circuit in communication with said imagingsubsystem; and an illumination subsystem comprising at least oneillumination light source for projecting an illumination pattern onto atarget, and at least one aiming light source for projecting an aimingpattern onto a target, wherein said at least one illumination lightsource and said at least one aiming light sources emit light ofdifferent visible colors, so that color contrast is present between saidillumination pattern and said aiming pattern.
 18. The reader of claim17, wherein both of said at least one illumination light source and saidaiming light source comprise LEDs.
 19. The optical reader of claim 17,wherein said illumination light source emits red light and said aiminglight source emits white light.
 20. The optical reader of claim 17,wherein illumination light source emits light selected from the groupconsisting of green and blue and said aiming light source emits redlight.
 21. The optical reader of claim 17, wherein illumination lightsource emits white light and said aiming illumination light source emitslight selected from the group consisting of red, green, blue, andyellow.
 22. The optical reader of claim 17, wherein illumination lightsource emits infrared light and said aiming light source emits lightselected from the group consisting of red, green, blue, yellow andwhite.
 23. The optical reader of claim 17, wherein illumination lightsource emits ultraviolet light and said aiming light source emits lightselected from the group consisting of red, green, blue, yellow andwhite.
 24. The optical reader of claim 17, wherein said at least one ofsaid illumination light source and said aiming light source comprises amultiple color-emitting light source, wherein a color emitted by saidmultiple color-emitting light source depends upon a value of a signal orsignals presented to said multiple color-emitting light source by saidcontrol circuit.
 25. The optical reader of claim 17, wherein saidoptical reader is of a type that may be operated in one of a pluralityof user-selectable operating modes, wherein said reader includes a menudriver for allowing a user to select one of said operating modes, eachof said mode selections being associated with a particular aimingpattern and illumination pattern color contrast combination, saidcontrol circuit being configured to control said illumination subsystemto generate a certain illumination pattern and aiming pattern colorcontract pattern when one of said modes is selected.
 26. The opticalreader of claim 25, wherein one of said user-selectable operating modesis a standard bar code reader operating mode and wherein said controlcircuit controls said illumination subsystem so that said at least oneillumination light source emits red light and said at least one aimingillumination light source emits green or blue light when said standardbar code reader operating mode is selected.
 27. The optical reader ofclaim 25, wherein one of said user-selectable operating modes is aflourescent postnet reading operating mode and wherein said controlcircuit controls said illumination subsystem so that said at least oneillumination light source emits green or blue light when and said atleast one aiming illumination light source emits red light when saidfluorescent orange postnet reading mode is selected.
 28. The opticalreader of claim 25, wherein one of said user-selectable operating modesis a red indicia reading mode and wherein said control circuit controlssaid illumination subsystem so that said at least one illumination lightsource emits white light when said at least one aiming illuminationlight source emits light selected from the group consisting of red,green, blue, and yellow when said red indicia reading mode is selected.29. The optical reader of claim 25, wherein one of said user-selectableoperating modes is a secure bar code reading mode and wherein saidcontrol circuit controls said illumination subsystem so that said atleast one illumination light source emits infrared light when and saidat least one aiming illumination light source emits light selected fromthe group consisting of red, green, blue, and yellow when said securebar code reading mode is selected.